VFS: add VOP_GETLOWVNODE()

It is similar to VOP_GETWRITEMOUNT(), and for given vnode vp should
return the lower vnode which would actually handle write to vp.
Flags allow to specify FREAD or FWRITE for benefit of possible unionfs
implementation.

Reviewed by: markj, Olivier Certner <olce.freebsd@certner.fr>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D42603

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

vfs: vn_dir_next_dirent(): Simplify interface and harden

Simplify the old interface (one less argument, simpler termination test)
and add documentation about it. Add more sanity checks (mostly under
INVARIANTS, but also in the general case to prevent infinite
loops). Drop the explicit test on minimum directory entry size (without
INVARIANTS).

Deal with the impacts in callers (dirent_exists() and vop_stdvptocnp()).
dirent_exists() has been simplified a bit, preserving the exact same
semantics but for the return code whose meaning has been reversed (0 now
means the entry exists, ENOENT that it doesn't and other values are
genuine errors). While here, suppress gratuitous casts of malloc return
values.

vn_dir_next_dirent() has been tested by a 'make -j4 buildkernel' with a
temporary modification to the VFS cache causing vn_vptocnp() to always
call VOP_VPTOCNP() and finally vop_stdvptocnp() (observed with temporary
debug counters).

Export new _GENERIC_MINDIRSIZ and _GENERIC_MAXDIRSIZ on __BSD_VISIBLE,
and GENERIC_MINDIRSIZ and GENERIC_MAXDIRSIZ on _KERNEL.

Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D39764

vfs: Export get_next_dirent() as vn_dir_next_dirent()

Move internal-to-'vfs_default.c' get_next_dirent() to 'vfs_vnops.c' and
export it for use by other parts of the VFS. This is a preparatory
change for using it in vfs_emptydir().

No functional change.

Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D39755

vfs: ansify

Reported by: clang 15
Sponsored by: Rubicon Communications, LLC ("Netgate")

vfs: NDFREE(&nd, NDF_ONLY_PNBUF) -> NDFREE_PNBUF(&nd)

vfs: fully lockless v_writecount adjustment

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D33128

vfs: replace the MNTK_TEXT_REFS flag with VIRF_TEXT_REF

This allows to stop maintaing the VI_TEXT_REF flag and consequently
opens up fully lockless v_writecount adjustment.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D33127

vfs: add vop_stdadd_writecount_nomsync

This avoids needing to inspect the mount point every time.

Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D33125

vfs: remove the unused thread argument from NDINIT*

See b4a58fbf640409a1 ("vfs: remove cn_thread")

Bump __FreeBSD_version to 1400043.

vfs: Add "ioflag" and "cred" arguments to VOP_ALLOCATE

When the NFSv4.2 server does a VOP_ALLOCATE(), it needs
the operation to be done for the RPC's credential and not
td_ucred. It also needs the writing to be done synchronously.

This patch adds "ioflag" and "cred" arguments to VOP_ALLOCATE()
and modifies vop_stdallocate() to use these arguments.

The VOP_ALLOCATE.9 man page will be patched separately.

Reviewed by: khng, kib
Differential Revision: https://reviews.freebsd.org/D32865

vfs_default: Change vop_stddeallocate() from static to global

A future commit to the NFS client uses vop_stddeallocate() for
cases where the NFS server does not support a Deallocate operation.
Change vop_stddeallocate() from static to global so that it can
be called by the NFS client.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D31640

fspacectl(2): Changes on rmsr.r_offset's minimum value returned

rmsr.r_offset now is set to rqsr.r_offset plus the number of bytes
zeroed before hitting the end-of-file. After this change rmsr.r_offset
no longer contains the EOF when the requested operation range is
completely beyond the end-of-file. Instead in such case rmsr.r_offset is
equal to rqsr.r_offset. Callers can obtain the number of bytes zeroed
by subtracting rqsr.r_offset from rmsr.r_offset.

Sponsored by: The FreeBSD Foundation
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D31677

fspacectl(2): Clarifies the return values

rmacklem@ spotted two things in the system call:
- Upon returning from a successful operation, vop_stddeallocate can
update rmsr.r_offset to a value greater than file size. This behavior,
although being harmless, can be confusing.
- The EINVAL return value for rqsr.r_offset + rqsr.r_len > OFF_MAX is
undocumented.

This commit has the following changes:
- vop_stddeallocate and shm_deallocate to bound the the affected area
further by the file size.
- The EINVAL case for rqsr.r_offset + rqsr.r_len > OFF_MAX is
documented.
- The fspacectl(2), vn_deallocate(9) and VOP_DEALLOCATE(9)'s return
len is explicitly documented the be the value 0, and the return offset
is restricted to be the smallest of off + len and current file size
suggested by kib@. This semantic allows callers to interact better
with potential file size growth after the call.

Sponsored by: The FreeBSD Foundation
Reviewed by: imp, kib
Differential Revision: https://reviews.freebsd.org/D31604

vfs: Add ioflag to VOP_DEALLOCATE(9)

The addition of ioflag allows callers passing
IO_SYNC/IO_DATASYNC/IO_DIRECT down to the file system implementation.
The vop_stddeallocate fallback implementation is updated to pass the
ioflag to the file system implementation. vn_deallocate(9) internally is
also changed to pass ioflag to the VOP_DEALLOCATE call.

Sponsored by: The FreeBSD Foundation
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D31500

Add fspacectl(2), vn_deallocate(9) and VOP_DEALLOCATE(9).

fspacectl(2) is a system call to provide space management support to
userspace applications. VOP_DEALLOCATE(9) is a VOP call to perform the
deallocation. vn_deallocate(9) is a public KPI for kmods' use.

The purpose of proposing a new system call, a KPI and a VOP call is to
allow bhyve or other hypervisor monitors to emulate the behavior of SCSI
UNMAP/NVMe DEALLOCATE on a plain file.

fspacectl(2) comprises of cmd and flags parameters to specify the
space management operation to be performed. Currently cmd has to be
SPACECTL_DEALLOC, and flags has to be 0.

fo_fspacectl is added to fileops.
VOP_DEALLOCATE(9) is added as a new VOP call. A trivial implementation
of VOP_DEALLOCATE(9) is provided.

Sponsored by: The FreeBSD Foundation
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D28347

VFS_QUOTACTL(9): allow implementation to indicate busy state changes

Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.

Also, add stbool.h to libprocstat modules which #define _KERNEL
before including sys/mount.h. Otherwise they'll pull in sys/types.h
before defining _KERNEL and therefore won't have the bool definition
they need for mp_busy.

Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30556

Revert commits 6d3e78ad6c11 and 54256e7954d7

Parts of libprocstat like to pretend they're kernel components for the
sake of including mount.h, and including sys/types.h in the _KERNEL
case doesn't fix the build for some reason. Revert both the
VFS_QUOTACTL() change and the follow-up "fix" for now.

VFS_QUOTACTL(9): allow implementation to indicate busy state changes

Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9). The implementation may then indicate to the caller
whether it needed to unbusy the mount.

Reviewed By: kib, markj
Differential Revision: https://reviews.freebsd.org/D30218

vfs: add missing atomic conversion to writecount adjustment

Fixes: ("vfs: lockless writecount adjustment in set/unset text")

vfs: lockless writecount adjustment in set/unset text

... for cases where this is not the first/last exec.

VOP_STAT: Provide a default value for va_gen

Some filesystems, e.g., pseudofs and the NFSv3 client, do not provide
one.

Reviewed by: kib
Reported by: KMSAN
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30091

vfs: add vfs_ref_from_vp

This generalizes what vop_stdgetwritemount used to be doing.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D28695

lockf: ensure atomicity of lockf for open(O_CREAT|O_EXCL|O_EXLOCK)

or EX_SHLOCK. Do it by setting a vnode iflag indicating that the locking
exclusive open is in progress, and not allowing F_LOCK request to make
a progress until the first open finishes.

Requested by: mckusick
Reviewed by: markj, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D28697

Add VOP_VPUT_PAIR() with trivial default implementation.

The VOP is intended to be used in situations where VFS has two
referenced locked vnodes, typically a directory vnode dvp and a vnode
vp that is linked from the directory, and at least dvp is vput(9)ed.
The child vnode can be also vput-ed, but optionally left referenced and
locked.

There, at least UFS may need to do some actions with dvp which cannot be
done while vp is also locked, so its lock might be dropped temporary.
For instance, in some cases UFS needs to sync dvp to avoid filesystem
state that is currently not handled by either kernel nor fsck. Having
such VOP provides the neccessary context for filesystem which can do
correct locking and handle potential reclamation of vp after relock.

Trivial implementation does vput(dvp) and optionally vput(vp).

Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

Make MAXPHYS tunable. Bump MAXPHYS to 1M.

Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.

Make b_pages[] array in struct buf flexible. Size b_pages[] for buffer
cache buffers exactly to atop(maxbcachebuf) (currently it is sized to
atop(MAXPHYS)), and b_pages[] for pbufs is sized to atop(maxphys) + 1.
The +1 for pbufs allow several pbuf consumers, among them vmapbuf(),
to use unaligned buffers still sized to maxphys, esp. when such
buffers come from userspace (*). Overall, we save significant amount
of otherwise wasted memory in b_pages[] for buffer cache buffers,
while bumping MAXPHYS to desired high value.

Eliminate all direct uses of the MAXPHYS constant in kernel and driver
sources, except a place which initialize maxphys. Some random (and
arguably weird) uses of MAXPHYS, e.g. in linuxolator, are converted
straight. Some drivers, which use MAXPHYS to size embeded structures,
get private MAXPHYS-like constant; their convertion is out of scope
for this work.

Changes to cam/, dev/ahci, dev/ata, dev/mpr, dev/mpt, dev/mvs,
dev/siis, where either submitted by, or based on changes by mav.

Suggested by: mav (*)
Reviewed by: imp, mav, imp, mckusick, scottl (intermediate versions)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D27225

vfs: group mount per-cpu vars into one struct

While here move frequently read stuff into the same cacheline.

This shrinks struct mount by 64 bytes.

Tested by: pho

vfs: drop spurious cred argument from VOP_VPTOCNP

vfs: add VOP_EAGAIN

Can be used to stub fplookup for example.

Convert page cache read to VOP.

There are several negative side-effects of not calling into VOP layer
at all for page cache reads. The biggest is the missed activation of
EVFILT_READ knotes.

Also, it allows filesystem to make more fine grained decision to
refuse read from page cache.

Keep VIRF_PGREAD flag around, it is still useful for nullfs, and for
asserts.

Reviewed by: markj
Tested by: pho
Discussed with: mjg
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346

vfs: assert that VI_TEXT_REF is not already set

vfs: remove the thread argument from vget

It was already asserted to be curthread.

Semantic patch:

@@

expression arg1, arg2, arg3;

@@

- vget(arg1, arg2, arg3)
+ vget(arg1, arg2)

vfs: add VOP_STAT

The current scheme of calling VOP_GETATTR adds avoidable overhead.

An example with tmpfs doing fstat (ops/s):
before: 7488958
after: 7913833

Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D25910

vfs: fold poll_no_poll into vop_nopoll

The logic was almost completely present in vop_stdpoll anyway.

VOP_GETPAGES_ASYNC(): consistently call iodone() callback in case of error.

Reviewed by: glebius, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24038

lockmgr: add a change missed in r357907

lockmgr: rename lock_fast_path to lock_flags

The routine is not much of a fast path and the flags name better describes
its purpose.

vfs: consistently use size_t for buflen around VOP_VPTOCNP

vfs: remove vop loop from vop_sigdefer

All ops are guaranteed to be present since r357131.

vfs: switch vop_stdunlock to call lockmgr_unlock

Since the flags argument is now alawys 0 the new call provides the same
behavior.

vfs: in vop_stdadd_writecount only vlazy vnodes on mounts using msync

The only reason to vlazy there is to (overzealously) ensure all vnodes
which need to be visited by msync scan can be found there.

In particluar this is of no use zfs and tmpfs.

While here depessimize the check.

vfs: add per-mount vnode lazy list and use it for deferred inactive + msync

This obviates the need to scan the entire active list looking for vnodes
of interest.

msync is handled by adding all vnodes with write count to the lazy list.

deferred inactive directly adds vnodes as it sets the VI_DEFINACT flag.

Vnodes get dequeued from the list when their hold count reaches 0.

Newly added MNT_VNODE_FOREACH_LAZY* macros support filtering so that
spurious locking is avoided in the common case.

Reviewed by: jeff
Tested by: pho (in a larger patch, previous version)
Differential Revision: https://reviews.freebsd.org/D22995

vfs: drop the mostly unused flags argument from VOP_UNLOCK

Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.

Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427

vfs: flatten vop vectors

This eliminates the following loop from all VOP calls:

while(vop != NULL && \
vop->vop_spare2 == NULL && vop->vop_bypass == NULL)
vop = vop->vop_default;

Reviewed by: jeff
Tesetd by: pho
Differential Revision: https://reviews.freebsd.org/D22738

r355677 requires that vop_stdioctl() be global so it can be called from NFS.

r355677 modified the NFS client so that it does lseek(SEEK_DATA/SEEK_HOLE)
for NFSv4.2, but calls vop_stdioctl() otherwise. As such, vop_stdioctl()
needs to be a global function.

Missed during the code merge for r355677.

vfs: locking primitives which elide ->v_vnlock and shared locking disablement

Both of these features are not needed by many consumers and result in avoidable
reads which in turn puts them on profiles due to cache-line ping ponging.

On top of that the current lockgmr entry point is slower than necessary
single-threaded. As an attempted clean up preparing for other changes,
provide new routines which don't support any of the aforementioned features.

With these patches in place vop_stdlock and vop_stdunlock disappear from
flamegraphs during -j 104 buildkernel.

Reviewed by: jeff (previous version)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22665

vfs: introduce v_irflag and make v_type smaller

The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.

v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.

Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715

vfs: apply r352437 to the fast path as well

This one is very hard to run into. If the filesystem is being unmounted or
the mount point is freed the vfs_op_thread_enter will fail. For it to
succeed the mount point itself would have to be reallocated in the time
window between the initial read and the attempt to enter.

Sponsored by: The FreeBSD Foundation

vfs: fix braino resulting in NULL pointer deref in r352424

The breakage was added after all the testing and the testing which followed
was not sufficient to find it.

Reported by: pho
Sponsored by: The FreeBSD Foundation

vfs: convert struct mount counters to per-cpu

There are 3 counters modified all the time in this structure - one for
keeping the structure alive, one for preventing unmount and one for
tracking active writers. Exact values of these counters are very rarely
needed, which makes them a prime candidate for conversion to a per-cpu
scheme, resulting in much better performance.

Sample benchmark performing fstatfs (modifying 2 out of 3 counters) on
a 104-way 2 socket Skylake system:
before: 852393 ops/s
after: 76682077 ops/s

Reviewed by: kib, jeff
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21637

vfs: manage mnt_ref with atomics

New primitive is introduced to denote sections can operate locklessly
on aspects of struct mount, but which can also be disabled if necessary.
This provides an opportunity to start scaling common case modifications
while providing stable state of the struct when facing unmount, write
suspendion or other events.

mnt_ref is the first counter to start being managed in this manner with
the intent to make it per-cpu.

Reviewed by: kib, jeff
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21425

vfs: restore mp null check in vop_stdgetwritemount

The initially read mount point can already be NULL.

Reported by: markj
Fixes: r351656 ("vfs: stop refing freed mount points in vop_stdgetwritemount")
Sponsored by: The FreeBSD Foundation

vfs: stop refing freed mount points in vop_stdgetwritemount

The code used blindly ref based on an unsafely red address and then would
backpedal if necessary. This was safe in terms of memory access since
mounts are type-stable, but made for a potential a bug where the mount
was reused and had the count reset to 0 before this code decreased it.

Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21411

vfs: add VOP_NEED_INACTIVE

vnode usecount drops to 0 all the time (e.g. for directories during path lookup).
When that happens the kernel would always lock the exclusive lock for the vnode
in order to call vinactive(). This blocks other threads who want to use the vnode
for looukp.

vinactive is very rarely needed and can be tested for without the vnode lock held.

This patch gives filesytems an opportunity to do it, sample total wait time for
tmpfs over 500 minutes of poudriere -j 104:

before: 557563641706 (lockmgr:tmpfs)
after: 46309603301 (lockmgr:tmpfs)

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21371

Add a vop_stdioctl() that performs a trivial FIOSEEKDATA/FIOSEEKHOLE.

Without this patch, when an application performed lseek(SEEK_DATA/SEEK_HOLE)
on a file in a file system that does not have its own VOP_IOCTL(), the
lseek(2) fails with errno ENOTTY. This didn't seem appropriate, since
ENOTTY is not listed as an error return by either the lseek(2) man page
nor the POSIX draft for lseek(2).
A discussion on freebsd-current@ seemed to indicate that implementing
a trivial algorithm that returns the offset argument for FIOSEEKDATA and
returns the file's size for FIOSEEKHOLE was the preferred fix.
http://docs.FreeBSD.org/cgi/mid.cgi?CAOtMX2iiQdv1+15e1N_r7V6aCx_VqAJCTP1AW+qs3Yg7sPg9wA
The Linux kernel appears to implement this trivial algorithm as well.

This patch adds a vop_stdioctl() that implements this trivial algorithm.
It returns errors consistent with vn_bmap_seekhole() and, as such, will
still return ENOTTY for non-regular files.

I have proposed a separate patch that maps errors not described by the
lseek(2) man page nor POSIX draft to EINVAL. This patch is under separate
review.

Reviewed by: kib
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D21299

Fix an issue with executing tmpfs binary.

Suppose that a binary was executed from tmpfs mount, and the text
vnode was reclaimed while the binary was still running. It is
possible during even the normal operations since tmpfs vnode'
vm_object has swap type, and no references on the vnode is held. Also
assume that the text vnode was revived for some reason. Then, on the
process exit or exec, unmapping of the text mapping tries to remove
the text reference from the vnode, but since it went from
recycle/instantiation cycle, there is no reference kept, and assertion
in VOP_UNSET_TEXT_CHECKED() triggers.

Fix this by keeping a use reference on the tmpfs vnode for each exec
reference. This prevents the vnode reclamation while executable map
entry is active.

Do it by adding per-mount flag MNTK_TEXT_REFS that directs
vop_stdset_text() to add use ref on first vnode text use, and
per-vnode VI_TEXT_REF flag, to record the need on unref in
vop_stdunset_text() on last vnode text use going away. Set
MNTK_TEXT_REFS for tmpfs mounts.

Reported by: bdrewery
Tested by: sbruno, pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Add kernel support for a Linux compatible copy_file_range(2) syscall.

This patch adds support to the kernel for a Linux compatible
copy_file_range(2) syscall and the related VOP_COPY_FILE_RANGE(9).
This syscall/VOP can be used by the NFSv4.2 client to implement the
Copy operation against an NFSv4.2 server to do file copies locally on
the server.
The vn_generic_copy_file_range() function in this patch can be used
by the NFSv4.2 server to implement the Copy operation.
Fuse may also me able to use the VOP_COPY_FILE_RANGE() method.

vn_generic_copy_file_range() attempts to maintain holes in the output
file in the range to be copied, but may fail to do so if the input and
output files are on different file systems with different _PC_MIN_HOLE_SIZE
values.

Separate commits will be done for the generated syscall files and userland
changes. A commit for a compat32 syscall will be done later.

Reviewed by: kib, asomers (plus comments by brooks, jilles)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D20584

Add a VOP_BMAP(9) man page

Reviewed by: mckusick
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20704

Silence witness warning about duplicated mutex type.

The order is correct, it is nullfs vnode interlock -> lower vnode
interlock. vop_stdadd_writecount() is called from nullfs
VOP_ADD_WRITECOUNT() and both take interlocks.

Requested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

Switch to use shared vnode locks for text files during image activation.

kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.

The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount. To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal

The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change. vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP. vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.

nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.

On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.

Reviewed by: markj, trasz
Tested by: mjg, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D19923

Add vn_fsync_buf().

Provide a convenience function to avoid the hack with filling fake
struct vop_fsync_args and then calling vop_stdfsync().

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Add _PC_ACL_* to vop_stdpathconf

This avoid EINVAL from tmpfs etc.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D19512

Oops, rounddown() for the start was misspelled roundup() in r342295,
so only aligned starts worked. This broke releasing caches in most
cases where the i/o size is smaller than the fs block size.

Fix rounding in vop_stdadvise() for POSIX_FADV_NOREUSE (really
POSIX_FADV_DONTNEED). The most broken case was for applications that
advise for the whole file and then do block-aligned i/o's 1 block at
a time. Then advice is sent to VOP_ADVISE() 1 block at a time, but
in vop_stdadvise() the 1-block advice was turned into 0-block advice
for the buffer cache part.

The bugs were caused partly by callers representing the region as
(a_start, a_end), where a_end is actually the maximum, and everything
else representing the region as (start, end) where 'end' is actually
the end (1 after the maximum). The maximum a_end must be rounded up,
but was rounded down. Also, rounding to page boundaries was inconsistent.

The bugs and fixes have no effect for zfs and other file systems that
don't use the buffer cache or the page cache. Most or all file systems
currently use the default VOP_FADVISE(), but it finds a null buffer cache
and a null page cache for file systems that don't use normal methods.

Reviewed by: kib

Only call sigdeferstop() for NFS.

Use bypass to catch any NFS VOP dispatch and route it through the
wrapper which does sigdeferstop() and then dispatches original
VOP. NFS does not need a bypass below it, which is not supported.

The vop offset in the vop_vector is added since otherwise it is
impossible to get vop_op_t from the internal table, and I did not
wanted to create the layered fs only to wrap NFS VOPs.

VFS_OP()s wrap is straightforward.

Requested and reviewed by: mjg (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D17658

vfs: simplify vop_stdlock/unlock

The interlock pointer is non-NULL by definition and the compiler see through
that and eliminates the NULL checks. Just remove them from the code as they
play no role.

No difference in generated assembly.

Include error number in the "fsync: giving up on dirty" message
(in case it ever starts happening again in spite of 328444).

Submitted by: Andreas Longwitz <longwitz at incore.de>

For many years the message "fsync: giving up on dirty" has occationally
appeared on UFS/FFS filesystems. In some cases it was promptly followed
by a panic of "softdep_deallocate_dependencies: dangling deps". This fix
should eliminate both of these occurences.

Submitted by: Andreas Longwitz <longwitz at incore.de>
Reviewed by: kib
Tested by: Peter Holm (pho)
PR: 225423
MFC after: 1 week

Rework pathconf handling for FIFOs.

On the one hand, FIFOs should respect other variables not supported by
the fifofs vnode operation (such as _PC_NAME_MAX, _PC_LINK_MAX, etc.).
These values are fs-specific and must come from a fs-specific method.
On the other hand, filesystems that support FIFOs are required to
support _PC_PIPE_BUF on directory vnodes that can contain FIFOs.
Given this latter requirement, once the fs-specific VOP_PATHCONF
method supports _PC_PIPE_BUF for directories, it is also suitable for
FIFOs permitting a single VOP_PATHCONF method to be used for both
FIFOs and non-FIFOs.

To that end, retire all of the FIFO-specific pathconf methods from
filesystems and change FIFO-specific vnode operation switches to use
the existing fs-specific VOP_PATHCONF method. For fifofs, set it's
VOP_PATHCONF to VOP_PANIC since it should no longer be used.

While here, move _PC_PIPE_BUF handling out of vop_stdpathconf() so that
only filesystems supporting FIFOs will report a value. In addition,
only report a valid _PC_PIPE_BUF for directories and FIFOs.

Discussed with: bde
Reviewed by: kib (part of a larger patch)
MFC after: 1 month
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D12572

Move NAME_MAX, LINK_MAX, and CHOWN_RESTRICTED out of vop_stdpathconf().

Having all filesystems fall through to default values isn't always correct
and these values can vary for different filesystem implementations. Most
of these changes just use the existing default values with a few exceptions:
- Don't report CHOWN_RESTRICTED for ZFS since it doesn't do the exact
permissions check this claims for chown().
- Use NANDFS_NAME_LEN for NAME_MAX for nandfs.
- Don't report a LINK_MAX of 0 on smbfs. Now fail with EINVAL to
indicate hard links aren't supported.

Requested by: bde (though perhaps not this exact implementation)
Reviewed by: kib (earlier version)
MFC after: 1 month
Sponsored by: Chelsio Communications

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Only handle _PC_MAX_CANON, _PC_MAX_INPUT, and _PC_VDISABLE for TTY devices.

Move handling of these three pathconf() variables out of vop_stdpathconf()
and into devfs_pathconf() as TTY devices can only be devfs files. In
addition, only return settings for these three variables for devfs devices
whose device switch has the D_TTY flag set.

Discussed with: bde, kib
Sponsored by: Chelsio Communications

For UNIX sockets make vnode point not to the socket, but to the UNIX PCB,
since the latter is the thing that links together VFS and sockets.

While here, make the union in the struct vnode anonymous.

Relax the locking requirements for vm_object_page_noreuse(). While
reviewing all uses of OFF_TO_IDX(), I observed that
vm_object_page_noreuse() is requiring an exclusive lock on the object
when, in fact, a shared lock suffices.

Reviewed by: kib, markj
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D10011

Make the code match the comments: If we have ANY buf's that failed
then return EAGAIN. The current code just returns that if the LAST buf
failed.

Reviewed by: kib@, trasz@
Differential Revision: https://reviews.freebsd.org/D9677

lockmgr: implement fast path

The main lockmgr routine takes 8 arguments which makes it impossible to
tail-call it by the intermediate vop_stdlock/unlock routines.

The routine itself starts with an if-forest and reads from the lock itself
several times.

This slows things down both single- and multi-threaded. With the patch
single-threaded fstats go 4% up and multithreaded up to ~27%.

Note that there is still a lot of room for improvement.

Reviewed by: kib
Tested by: pho

Do not allocate struct statfs on kernel stack.

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

Renumber license clauses in sys/kern to avoid skipping #3

Implement VOP_FDATASYNC() for msdosfs.

Standard VOP_FSYNC() implementation just syncs data buffers, and due
to this, is the correct and efficient implementation for msdosfs or
any other filesystem which uses bufer cache trivially. Provide
globally visible wrapper vop_stdfdatasync_buf() for future consumption
by other filesystems.

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D7471

Add an implementation of fdatasync(2).

The syscall is a trivial wrapper around new VOP_FDATASYNC(), sharing
code with fsync(2). For all filesystems, this commit provides the
implementation which delegates the work of VOP_FDATASYNC() to
VOP_FSYNC(). This is functionally correct but not efficient.

This is not yet POSIX-compliant implementation, because it does not
ensure that queued AIO requests are completed before returning.

Reviewed by: mckusick
Discussed with: avg (ZFS), jhb (AIO part)
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D7471

VOP_FSYNC() does not take cred as an argument. Correct comment.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Replace all remaining calls to vprint(9) with vn_printf(9), and remove
the old macro.

MFC after: 1 month

Simplify AIO initialization now that it is standard.

- Mark AIO system calls as STD and remove the helpers to dynamically
register them.
- Use COMPAT6 for the old system calls with the older sigevent instead of
an 'o' prefix.
- Simplify the POSIX configuration to note that AIO is always available.
- Handle AIO in the default VOP_PATHCONF instead of special casing it in
the pathconf() system call. fpathconf() is still hackish.
- Remove freebsd32_aio_cancel() as it just called the native one directly.

Reviewed by: kib
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D5589

Two fixes for excessive iterations after r292326.

Advance the logical block number to the lblkno of the found block plus
one, instead of incrementing the block number which was used for
lookup. This change skips sparcely populated buffer ranges, similar
to r292325, instead of doing useless lookups.

Do not restart the bnoreuselist() from the start of the range if
buffer lock cannot be obtained without sleep. Only retry lookup and
lock for the same queue and same logical block number.

Reported by: benno
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 days

A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES().

o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return, like it was
done before with the 'reqpage' only. Now the reqpage goes away. With
new interface it is easier to implement code protected from race
conditions.

Such arrayed requests for now should be preceeded by a call to
vm_pager_haspage() to make sure that request is possible. This
could be improved later, making vm_pager_haspage() obsolete.

Strenghtening the promises on the business of the array of pages
allows us to remove such hacks as swp_pager_free_nrpage() and
vm_pager_free_nonreq().

o New KPI accepts two integer pointers that may optionally point at
values for read ahead and read behind, that a pager may do, if it
can. These pages are completely owned by pager, and not controlled
by the caller.

This shifts the UFS-specific readahead logic from vm_fault.c, which
should be file system agnostic, into vnode_pager.c. It also removes
one VOP_BMAP() request per hard fault.

Discussed with: kib, alc, jeff, scottl
Sponsored by: Nginx, Inc.
Sponsored by: Netflix

Optimize vop_stdadvise(POSIX_FADV_DONTNEED). Instead of looking up a
buffer for each block number in the range with gbincore(), look up the
next instantiated buffer with the logical block number which is
greater or equal to the next lblkno. This significantly speeds up the
iteration for sparce-populated range.

Move the iteration into new helper bnoreuselist(), which is structured
similarly to flushbuflist().

Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation

Ensure that vop_stdadvise() does not call getblk() on vnodes that have an
empty bufobj. Otherwise, vnodes belonging to filesystems that do not use the
buffer cache may trigger assertion failures.

Reported by: Fabien Keil

As a step towards the elimination of PG_CACHED pages, rework the handling
of POSIX_FADV_DONTNEED so that it causes the backing pages to be moved to
the head of the inactive queue instead of being cached.

This affects the implementation of POSIX_FADV_NOREUSE as well, since it
works by applying POSIX_FADV_DONTNEED to file ranges after they have been
read or written. At that point the corresponding buffers may still be
dirty, so the previous implementation would coalesce successive ranges and
apply POSIX_FADV_DONTNEED to the result, ensuring that pages backing the
dirty buffers would eventually be cached. To preserve this behaviour in an
efficient manner, this change adds a new buf flag, B_NOREUSE, which causes
the pages backing a VMIO buf to be placed at the head of the inactive queue
when the buf is released. POSIX_FADV_NOREUSE then works by setting this
flag in bufs that underlie the specified range.

Reviewed by: alc, kib
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3726

vfs: use shared vnode locking when looking up ".." in vop_stdvptocnp

Briefly discussed with: kib

Fix the comment introduced in r276192 so that it clearly
states that the change is needed to avoid a deadlock.

Suggested by: kib
MFC after: 1 week

Modify vop_stdadvlock{async}() so that it only
locks/unlocks the vnode and does a VOP_GETATTR()
for the SEEK_END case. This is safe to do, since
lf_advlock{async}() only uses the size argument
for the SEEK_END case.
The NFSv4 server needs this when
vfs.nfsd.enable_locallocks!=0 since locking the
vnode results in a LOR that can cause a deadlock
for the nfsd threads.

Reviewed by: kib
MFC after: 1 week

Merge from projects/sendfile:

o Provide a new VOP_GETPAGES_ASYNC(), which works like VOP_GETPAGES(), but
doesn't sleep. It returns immediately, and will execute the I/O done handler
function that must be supplied as argument.
o Provide VOP_GETPAGES_ASYNC() for the FFS, which uses vnode_pager.
o Extend pagertab to support pgo_getpages_async method, and implement this
method for vnode_pager.

Reviewed by: kib
Tested by: pho
Sponsored by: Netflix
Sponsored by: Nginx, Inc.

Remove unused arguments for VOP_GETPAGES(), VOP_PUTPAGES().

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

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

Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
- VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
- VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
- VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
- VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
(in order to avoid visibility of implementation details)
- The read-mode operations are added:
VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
sys/mutex.h in consumers directly to cater its inlining functions
using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
the compat layer because the name clash between FreeBSD and solaris
versions must be avoided.
At this purpose zfs redefines the vm_object locking functions
directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit. Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by: EMC / Isilon storage division
Reviewed by: jeff
Reviewed by: pjd (ZFS specific review)
Discussed with: alc
Tested by: pho

Make the default implementation of the VOP_VPTOCNP() fail if the
directory entry, matched by the inode number, is ".".

NFSv4 client might instantiate the distinct vnodes which have the same
inode number, since single v4 export can be combined from several
filesystems on the server. For instance, a case when the nested
server mount point is exactly one directory below the top of the
export, causes directory and its parent to have the same inode number
2. The vop_stdvptocnp() algorithm then returns "." as the name of the
lower directory.

Filtering out the "." entry with ENOENT works around this behaviour,
the error forces getcwd(3) to fall back to usermode implementation,
which compares both st_dev and st_ino.

Based on the submission by: rmacklem
Tested by: rmacklem
MFC after: 1 week

The r241025 fixed the case when a binary, executed from nullfs mount,
was still possible to open for write from the lower filesystem. There
is a symmetric situation where the binary could already has file
descriptors opened for write, but it can be executed from the nullfs
overlay.

Handle the issue by passing one v_writecount reference to the lower
vnode if nullfs vnode has non-zero v_writecount. Note that only one
write reference can be donated, since nullfs only keeps one use
reference on the lower vnode. Always use the lower vnode v_writecount
for the checks.

Introduce the VOP_GET_WRITECOUNT to read v_writecount, which is
currently always bypassed to the lower vnode, and VOP_ADD_WRITECOUNT
to manipulate the v_writecount value, which manages a single bypass
reference to the lower vnode. Caling the VOPs instead of directly
accessing v_writecount provide the fix described in the previous
paragraph.

Tested by: pho
MFC after: 3 weeks

Remove the support for using non-mpsafe filesystem modules.

In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.

The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.

Conducted and reviewed by: attilio
Tested by: pho

Fix the mis-handling of the VV_TEXT on the nullfs vnodes.

If you have a binary on a filesystem which is also mounted over by
nullfs, you could execute the binary from the lower filesystem, or
from the nullfs mount. When executed from lower filesystem, the lower
vnode gets VV_TEXT flag set, and the file cannot be modified while the
binary is active. But, if executed as the nullfs alias, only the
nullfs vnode gets VV_TEXT set, and you still can open the lower vnode
for write.

Add a set of VOPs for the VV_TEXT query, set and clear operations,
which are correctly bypassed to lower vnode.

Tested by: pho (previous version)
MFC after: 2 weeks

When synchronously syncing a device (MNT_WAIT), wait for buffers
to become available. Otherwise we may excessively spin and fail
with ``fsync: giving up on dirty''.

Reviewed by: kib
Tested by: Peter Holm
MFC after: 1 week

Skip directory entries with zero inode number during traversal.

Entries with zero inode number are considered placeholders by libc and
UFS. Fix remaining uses of VOP_READDIR in kernel: vop_stdvptocnp,
unionfs.

Sponsored by: Google Summer of Code 2011

Replace the MNT_VNODE_FOREACH interface with MNT_VNODE_FOREACH_ALL.
The primary changes are that the user of the interface no longer
needs to manage the mount-mutex locking and that the vnode that
is returned has its mutex locked (thus avoiding the need to check
to see if its is DOOMED or other possible end of life senarios).

To minimize compatibility issues for third-party developers, the
old MNT_VNODE_FOREACH interface will remain available so that this
change can be MFC'ed to 9. Following the MFC to 9, MNT_VNODE_FOREACH
will be removed in head.

The reason for this update is to prepare for the addition of the
MNT_VNODE_FOREACH_ACTIVE interface that will loop over just the
active vnodes associated with a mount point (typically less than
1% of the vnodes associated with the mount point).

Reviewed by: kib
Tested by: Peter Holm
MFC after: 2 weeks

Introduce VOP_UNP_BIND(), VOP_UNP_CONNECT(), and VOP_UNP_DETACH()
operations for setting and accessing vnode's v_socket field.

The operations are necessary to implement proper unix socket handling
on layered file systems like nullfs(5).

This change fixes the long standing issue with nullfs(5) being in that
unix sockets did not work between lower and upper layers: if we bound
to a socket on the lower layer we could connect only to the lower
path; if we bound to the upper layer we could connect only to the
upper path. The new behavior is one can connect to both the lower and
the upper paths regardless what layer path one binds to.

PR: kern/51583, kern/159663
Suggested by: kib
Reviewed by: arch
MFC after: 2 weeks

Existing VOP_VPTOCNP() interface has a fatal flow that is critical for
nullfs. The problem is that resulting vnode is only required to be
held on return from the successfull call to vop, instead of being
referenced.

Nullfs VOP_INACTIVE() method reclaims the vnode, which in combination
with the VOP_VPTOCNP() interface means that the directory vnode
returned from VOP_VPTOCNP() is reclaimed in advance, causing
vn_fullpath() to error with EBADF or like.

Change the interface for VOP_VPTOCNP(), now the dvp must be
referenced. Convert all in-tree implementations of VOP_VPTOCNP(),
which is trivial, because vhold(9) and vref(9) are similar in the
locking prerequisites. Out-of-tree fs implementation of VOP_VPTOCNP(),
if any, should have no trouble with the fix.

Tested by: pho
Reviewed by: mckusick
MFC after: 3 weeks (subject of re approval)

Add the posix_fadvise(2) system call. It is somewhat similar to
madvise(2) except that it operates on a file descriptor instead of a
memory region. It is currently only supported on regular files.

Just as with madvise(2), the advice given to posix_fadvise(2) can be
divided into two types. The first type provide hints about data access
patterns and are used in the file read and write routines to modify the
I/O flags passed down to VOP_READ() and VOP_WRITE(). These modes are
thus filesystem independent. Note that to ease implementation (and
since this API is only advisory anyway), only a single non-normal
range is allowed per file descriptor.

The second type of hints are used to hint to the OS that data will or
will not be used. These hints are implemented via a new VOP_ADVISE().
A default implementation is provided which does nothing for the WILLNEED
request and attempts to move any clean pages to the cache page queue for
the DONTNEED request. This latter case required two other changes.
First, a new V_CLEANONLY flag was added to vinvalbuf(). This requests
vinvalbuf() to only flush clean buffers for the vnode from the buffer
cache and to not remove any backing pages from the vnode. This is
used to ensure clean pages are not wired into the buffer cache before
attempting to move them to the cache page queue. The second change adds
a new vm_object_page_cache() method. This method is somewhat similar to
vm_object_page_remove() except that instead of freeing each page in the
specified range, it attempts to move clean pages to the cache queue if
possible.

To preserve the ABI of struct file, the f_cdevpriv pointer is now reused
in a union to point to the currently active advice region if one is
present for regular files.

Reviewed by: jilles, kib, arch@
Approved by: re (kib)
MFC after: 1 month

Add a lock flags argument to the VFS_FHTOVP() file system
method, so that callers can indicate the minimum vnode
locking requirement. This will allow some file systems to choose
to return a LK_SHARED locked vnode when LK_SHARED is specified
for the flags argument. This patch only adds the flag. It
does not change any file system to use it and all callers
specify LK_EXCLUSIVE, so file system semantics are not changed.

Reviewed by: kib

Allow VOP_ALLOCATE to be iterative, and have kern_posix_fallocate(9)
drive looping and potentially yielding.

Requested by: kib

Add the posix_fallocate(2) syscall. The default implementation in
vop_stdallocate() is filesystem agnostic and will run as slow as a
read/write loop in userspace; however, it serves to correctly
implement the functionality for filesystems that do not implement a
VOP_ALLOCATE.

Note that __FreeBSD_version was already bumped today to 900036 for any
ports which would like to use this function.

Also reserve space in the syscall table for posix_fadvise(2).

Reviewed by: -arch (previous version)

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

If we read zero bytes from the directory, early out with ENOENT
rather than forging ahead and interpreting garbage buffer content
and dirent structures.

This change backs out r211684 which was essentially a no-op.

MFC after: 1 week

uio_resid isn't updated by VOP_READDIR for nfs filesystems. Use
the uio_offset adjustment instead to calculate a correct *len.

Without this change, we run off the end of the directory data
we're reading and panic horribly for nfs filesystems.

MFC after: 1 week

Add VOP_ADVLOCKPURGE so that the file system is called when purging
locks (in the case where the VFS impl isn't using lf_*)

Submitted by: Matthew Fleming <matthew.fleming@isilon.com>
Reviewed by: zml, dfr

MFC r206094:
Supply default implementation of VOP_RENAME() that does neccessary
unlocks and unreferences for argument vnodes, as expected by
kern_renameat(9), and returns EOPNOTSUPP. This fixes locks and
reference leaks when rename is attempted on fs that does not
implement rename.

Supply default implementation of VOP_RENAME() that does neccessary
unlocks and unreferences for argument vnodes, as expected by
kern_renameat(9), and returns EOPNOTSUPP. This fixes locks and
reference leaks when rename is attempted on fs that does not
implement rename.

PR: kern/107439
Based on submission by: Mikolaj Golub <to.my.trociny gmail com>
Tested by: Mikolaj Golub
MFC after: 1 week

MFC r197680:

Provide default implementation for VOP_ACCESS(9), so that filesystems which
want to provide VOP_ACCESSX(9) don't have to implement both. Note that
this commit makes implementation of either of these two mandatory.

Reviewed by: kib

Use vput() instead of VOP_UNLOCK()+vrele(). The comment here is out-dated,
we no longer pass thread pointer to VOP_UNLOCK().

Revert r198873. Having different VAPPEND semantics for VOP_ACCESS(9)
and VOP_ACCESSX(9) is not a good idea.

While VAPPEND without VWRITE makes sense for VOP_ACCESSX(9) (e.g. to check
for the permission to create subdirectory (ACE4_ADD_SUBDIRECTORY)), it doesn't
really make sense for VOP_ACCESS(9). Also, many VOP_ACCESS(9) implementations
don't expect that. Make sure we don't confuse them.

Provide default implementation for VOP_ACCESS(9), so that filesystems which
want to provide VOP_ACCESSX(9) don't have to implement both. Note that
this commit makes implementation of either of these two mandatory.

Reviewed by: kib

Add explicit struct ucred * argument for VOP_VPTOCNP, to be used by
vn_open_cred in default implementation. Valid struct ucred is needed for
audit and MAC, and curthread credentials may be wrong.

This further requires modifying the interface of vn_fullpath(9), but it
is out of scope of this change.

Reviewed by: rwatson

Add another flags argument to vn_open_cred. Use it to specify that some
vn_open_cred invocations shall not audit namei path.

In particular, specify VN_OPEN_NOAUDIT for dotdot lookup performed by
default implementation of vop_vptocnp, and for the open done for core
file. vn_fullpath is called from the audit code, and vn_open there need
to disable audit to avoid infinite recursion. Core file is created on
return to user mode, that, in particular, happens during syscall return.
The creation of the core file is audited by direct calls, and we do not
want to overwrite audit information for syscall.

Reported, reviewed and tested by: rwatson

Add mac_framework.h include missed when MAC code was (presumably) copied
from another file.

Add VOP_ACCESSX, which can be used to query for newly added V*
permissions, such as VWRITE_ACL. For a filsystems that don't
implement it, there is a default implementation, which works
as a wrapper around VOP_ACCESS.

Reviewed by: rwatson@

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.

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

Add a default implementation for VOP_VPTOCNP(9) which scans the parent
directory of a vnode to find a dirent with a matching file number. The
name from that dirent is then used to provide the component name.

Note: if the initial vnode argument is not a directory itself, then
the default VOP_VPTOCNP(9) implementation still returns ENOENT.

Reviewed by: kib
Approved by: kib
Tested by: pho

Extract the no_poll() and vop_nopoll() code into the common routine
poll_no_poll().
Return a poll_no_poll() result from devfs_poll_f() when
filedescriptor does not reference the live cdev, instead of ENXIO.

Noted and tested by: hps
MFC after: 1 week

Add a new VOP, VOP_VPTOCNP, which translates a vnode to its component name
on a best-effort basis. Teach vn_fullpath to use this new VOP if a
regular VFS cache lookup fails. This VOP is designed to supplement the
VFS cache to provide a better chance that a vnode-to-name lookup will
succeed.

Currently, an implementation for devfs is being committed. The default
implementation is to return ENOENT.

A big thanks to kib for the mentorship on this, and to pho for running it
through his stress test suite.

Reviewed by: arch
Approved by: kib

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

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>

Move the head of byte-level advisory lock list from the
filesystem-specific vnode data to the struct vnode. Provide the
default implementation for the vop_advlock and vop_advlockasync.
Purge the locks on the vnode reclaim by using the lf_purgelocks().
The default implementation is augmented for the nfs and smbfs.
In the nfs_advlock, push the Giant inside the nfs_dolock.

Before the change, the vop_advlock and vop_advlockasync have taken the
unlocked vnode and dereferenced the fs-private inode data, racing with
with the vnode reclamation due to forced unmount. Now, the vop_getattr
under the shared vnode lock is used to obtain the inode size, and
later, in the lf_advlockasync, after locking the vnode interlock, the
VI_DOOMED flag is checked to prevent an operation on the doomed vnode.

The implementation of the lf_purgelocks() is submitted by dfr.

Reported by: kris
Tested by: kris, pho
Discussed with: jeff, dfr
MFC after: 2 weeks

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

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

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>

- Introduce lockmgr_args() in the lockmgr space. This function performs
the same operation of lockmgr() but accepting a custom wmesg, prio and
timo for the particular lock instance, overriding default values
lkp->lk_wmesg, lkp->lk_prio and lkp->lk_timo.
- Use lockmgr_args() in order to implement BUF_TIMELOCK()
- Cleanup BUF_LOCK()
- Remove LK_INTERNAL as it is nomore used in the lockmgr namespace

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

Cleanup lockmgr interface and exported KPI:
- Remove the "thread" argument from the lockmgr() function as it is
always curthread now
- Axe lockcount() function as it is no longer used
- Axe LOCKMGR_ASSERT() as it is bogus really and no currently used.
Hopefully this will be soonly replaced by something suitable for it.
- Remove the prototype for dumplockinfo() as the function is no longer
present

Addictionally:
- Introduce a KASSERT() in lockstatus() in order to let it accept only
curthread or NULL as they should only be passed
- Do a little bit of style(9) cleanup on lockmgr.h

KPI results heavilly broken by this change, so manpages and
FreeBSD_version will be modified accordingly by further commits.

Tested by: matteo

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>

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.

Remove VFS_VPTOFH entirely. API is already broken and it is good time to
do it.

Suggested by: rwatson

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

change vop_lock handling to allowing tracking of callers' file and line for
acquisition of lockmgr locks

Approved by: scottl (standing in for mentor rwatson)

Don't try to obtain a reference to a nonexisting (NULL) mount structure in
default VOP_GETWRITEMOUNT().

- GETWRITEMOUNT now returns a referenced mountpoint to prevent its
identity from changing. This is possible now that mounts are not freed.

Discussed with: tegge
Tested by: kris
Sponsored by: Isilon Systems, Inc.

- Add a comment warning about an anomalous condition where we VOP_UNLOCK
and then vrele rather than vput because we would like to VOP_UNLOCK with
a specific thread.

Add marker vnodes to ensure that all vnodes associated with the mount point are
iterated over when using MNT_VNODE_FOREACH.

Reviewed by: truckman

Eradicate caddr_t from the VFS API.

In vop_stdpathconf(ap) also default for _PC_NAME_MAX and _PC_PATH_MAX.

- Replace the series of DEBUG_LOCKS hacks which tried to save the vn_lock
caller by saving the stack of the last locker/unlocker in lockmgr. We
also put the stack in KTR at the moment.

Contributed by: Antoine Brodin <antoine.brodin@laposte.net>

- Add and enhance asserts related to the wrong bufobj panic.

Sponsored by: Isilon Systems, Inc.
Approved by: re (blanket vfs)

Allow EVFILT_VNODE events to work on every filesystem type, not just
UFS by:
- Making the pre and post hooks for the VOP functions work even when
DEBUG_VFS_LOCKS is not defined.
- Moving the KNOTE activations into the corresponding VOP hooks.
- Creating a MNTK_NOKNOTE flag for the mnt_kern_flag field of struct
mount that permits filesystems to disable the new behavior.
- Creating a default VOP_KQFILTER function: vfs_kqfilter()

My benchmarks have not revealed any performance degradation.

Reviewed by: jeff, bde
Approved by: rwatson, jmg (kqueue changes), grehan (mentor)

- Remove unnecessary spls.

- Now that writes to character devices supporting softupdates can
generate dirty bufs even with a locked vnode, 100 retries is not that
many. This should probably change from a retry count to an abort when
we are no longer cleaning any buffers.
- Don't call vprint() while we still hold the vnode locked. Move the call
to later in the function.
- Clean up a comment.

- Fixup the default vfs_root function to match the new prototype.

Sponsored by: Isilon Systems, Inc.

- Don't drop the lock in the default inactive handler anymore, VOP_NULL
will do for vop_stdinactive now.

Sponsored by: Isilon Systems, Inc.

Remove VFS_START(). Its original purpose involved the mfs filesystem,
which is long gone.

Discussed with: mckusick
Reviewed by: phk

Remove vop_stddestroyvobject()

Move the contents of vop_stddestroyvobject() to the new vnode_pager
function vnode_destroy_vobject().

Make the new function zero the vp->v_object pointer so we can tell
if a call is missing.

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.

Move the body of vop_stdcreatevobject() over to the vnode_pager under
the name Sande^H^H^H^H^Hvnode_create_vobject().

Make the new function take a size argument which removes the need for
a VOP_STAT() or a very pessimistic guess for disks.

Call that new function from vop_stdcreatevobject().

Make vnode_pager_alloc() private now that its only user came home.

Kill the VV_OBJBUF and test the v_object for NULL instead.

- Remove GIANT_REQUIRED where it is no longer required.

Sponsored By: Isilon Systems, Inc.

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

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

Add missing vop_bypass (returning EOPNOTSUPP).

Tripped up: marks

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)

Make more sense out of vop_stdcreatevobject()

Make VOP_BMAP return a struct bufobj for the underlying storage device
instead of a vnode for it.

The vnode_pager does not and should not have any interest in what
the filesystem uses for backend.

(vfs_cluster doesn't use the backing store argument.)

The default VOP_REVOKE() should be vop_panic() as we should never
get here in the first place.

Properly implement a default version of VOP_GETWRITEMOUNT.

Remove improper access to vop_stdgetwritemount() which should and
will instead rely on the VOP default path.

Move a call to wakeup() from vm_object_terminate() to vnode_pager_dealloc()
because this call is only needed to wake threads that slept when they
discovered a dead object connected to a vnode. To eliminate unnecessary
calls to wakeup() by vnode_pager_dealloc(), introduce a new flag,
OBJ_DISCONNECTWNT.

Reviewed by: tegge@

Remove VOP_SPECSTRATEGY() from the system.

Eliminate unnecessary KASSERT.

Eliminate a printf which would never tell us anything anyway because the
KASSERT would have triggered.

Loose the v_dirty* and v_clean* alias macros.

Check the count field where we just want to know the full/empty state,
rather than using TAILQ_EMPTY() or TAILQ_FIRST().

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

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

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

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

Use vn_isdisk() to check if vnode is a disk.

(repeat, CVS core dumped on me)

use vn_isdisk() to see if vnode is a disk.

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.

style(9)

do the vfsstd thing instead of messing up our VFS_SYSCTL macro.

When we traverse the vnodes on a mountpoint we need to look out for
our cached 'next vnode' being removed from this mountpoint. If we
find that it was recycled, we restart our traversal from the start
of the list.

Code to do that is in all local disk filesystems (and a few other
places) and looks roughly like this:

MNT_ILOCK(mp);
loop:
for (vp = TAILQ_FIRST(&mp...);
(vp = nvp) != NULL;
nvp = TAILQ_NEXT(vp,...)) {
if (vp->v_mount != mp)
goto loop;
MNT_IUNLOCK(mp);
...
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);

The code which takes vnodes off a mountpoint looks like this:

MNT_ILOCK(vp->v_mount);
...
TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
...
MNT_IUNLOCK(vp->v_mount);
...
vp->v_mount = something;

(Take a moment and try to spot the locking error before you read on.)

On a SMP system, one CPU could have removed nvp from our mountlist
but not yet gotten to assign a new value to vp->v_mount while another
CPU simultaneously get to the top of the traversal loop where it
finds that (vp->v_mount != mp) is not true despite the fact that
the vnode has indeed been removed from our mountpoint.

Fix:

Introduce the macro MNT_VNODE_FOREACH() to traverse the list of
vnodes on a mountpoint while taking into account that vnodes may
be removed from the list as we go. This saves approx 65 lines of
duplicated code.

Split the insmntque() which potentially moves a vnode from one mount
point to another into delmntque() and insmntque() which does just
what the names say.

Fix delmntque() to set vp->v_mount to NULL while holding the
mountpoint lock.

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Clean up the stub fake vnode locking implemenations. The main reason this
stuff was here (NFS) was fixed by Alfred in November. The only remaining
consumer of the stub functions was umapfs, which is horribly horribly
broken. It has missed out on about the last 5 years worth of maintenence
that was done on nullfs (from which umapfs is derived). It needs major
work to bring it up to date with the vnode locking protocol. umapfs really
needs to find a caretaker to bring it into the 21st century.

Functions GC'ed:
vop_noislocked, vop_nolock, vop_nounlock, vop_sharedlock.

Remove mntvnode_mtx and replace it with per-mountpoint mutex.
Introduce two new macros MNT_ILOCK(mp)/MNT_IUNLOCK(mp) to
operate on this mutex transparently.

Eventually new mutex will be protecting more fields in
struct mount, not only vnode list.

Discussed with: jeff

Take care not to call vput if thread used in corresponding vget
wasn't curthread, i.e. when we receive a thread pointer to use
as a function argument. Use VOP_UNLOCK/vrele in these cases.

The only case there td != curthread known at the moment is
boot() calling sync with thread0 pointer.

This fixes the panic on shutdown people have reported.

Temporarily undo parts of the stuct mount locking commit by jeff.
It is unsafe to hold a mutex across vput/vrele calls.

This will be redone when a better locking strategy is agreed upon.

Discussed with: jeff

Relock mntvnode_mtx if vget fails in vfs_stdsync. The loop is
always shoould entered with mutex locked.

Introduce no_poll() default method for device drivers. Have it
do exactly the same as vop_nopoll() for consistency and put a
comment in the two pointing at each other.

Retire seltrue() in favour of no_poll().

Create private default functions in kern_conf.c instead of public
ones.

Change default strategy to return the bio with ENODEV instead of
doing nothing which would lead the bio stranded.

Retire public nullopen() and nullclose() as well as the entire band
of public no{read,write,ioctl,mmap,kqfilter,strategy,poll,dump}
funtions, they are the default actions now.

Move the final two trivial functions from subr_xxx.c to kern_conf.c
and retire the now empty subr_xxx.c

I have not had any reports of trouble for a long time, so remove the
gentle versions of the vop_strategy()/vop_specstrategy() mismatch methods
and use vop_panic() instead.

Use __FBSDID().

Lock the vm_object when performing vm_pager_deallocate().

Lock access to the vm_object's flags in vop_stdcreatevobject().

Lock an update to a vm_object's ref_count.

Deprecate machine/limits.h in favor of new sys/limits.h.
Change all in-tree consumers to include <sys/limits.h>

Discussed on: standards@
Partially submitted by: Craig Rodrigues <rodrigc@attbi.com>

- Lock the vm_object on entry to vm_object_terminate().

- Remove a race between fsync like functions and flushbufqueues() by
requiring locked bufs in vfs_bio_awrite(). Previously the buf could
have been written out by fsync before we acquired the buf lock if it
weren't for giant. The cluster_wbuild() handles this race properly but
the single write at the end of vfs_bio_awrite() would not.
- Modify flushbufqueues() so there is only one copy of the loop. Pass a
parameter in that says whether or not we should sync bufs with deps.
- Call flushbufqueues() a second time and then break if we couldn't find
any bufs without deps.

Rename vfs_stdsync function to vfs_stdnosync which matches more
closely what function is really doing. Update all existing consumers
to use the new name.

Introduce a new vfs_stdsync function, which iterates over mount
point's vnodes and call FSYNC on each one of them in turn.

Make nwfs and smbfs use this new function instead of rolling their
own identical sync implementations.

Reviewed by: jeff

Remove trainling whitespace.

Respect any passed in external lockmgr flags such as LK_NOWAIT in the
default implementations of VOP_LOCK() and VOP_UNLOCK().

Tested by: jlemon, phk
Glanced at by: jeffr

- Correct the wchan in vop_stdfsync()

This is almost what bde asked for. There is some desire to have per fs wchans
still but that is difficult giving the current arrangement of the code.

Pick up one file missed in the previous vprint() cleanup

- Add an interlock argument to BUF_LOCK and BUF_TIMELOCK.
- Remove the buftimelock mutex and acquire the buf's interlock to protect
these fields instead.
- Hold the vnode interlock while locking bufs on the clean/dirty queues.
This reduces some cases from one BUF_LOCK with a LK_NOWAIT and another
BUF_LOCK with a LK_TIMEFAIL to a single lock.

Reviewed by: arch, mckusick

- Claim we're 'fsync' and not 'spec_fsync' in vop_stdfsync.

- Cleanup unlocked accesses to buf flags by introducing a new b_vflag member
that is protected by the vnode lock.
- Move B_SCANNED into b_vflags and call it BV_SCANNED.
- Create a vop_stdfsync() modeled after spec's sync.
- Replace spec_fsync, msdos_fsync, and hpfs_fsync with the stdfsync and some
fs specific processing. This gives all of these filesystems proper
behavior wrt MNT_WAIT/NOWAIT and the use of the B_SCANNED flag.
- Annotate the locking in buf.h

Temporarily introduce a new VOP_SPECSTRATEGY operation while I try
to sort out disk-io from file-io in the vm/buffer/filesystem space.

The intent is to sort VOP_STRATEGY calls into those which operate
on "real" vnodes and those which operate on VCHR vnodes. For
the latter kind, the call will be changed to VOP_SPECSTRATEGY,
possibly conditionally for those places where dual-use happens.

Add a default VOP_SPECSTRATEGY method which will call the normal
VOP_STRATEGY. First time it is called it will print debugging
information. This will only happen if a normal vnode is passed
to VOP_SPECSTRATEGY by mistake.

Add a real VOP_SPECSTRATEGY in specfs, which does what VOP_STRATEGY
does on a VCHR vnode today.

Add a new VOP_STRATEGY method in specfs to catch instances where
the conversion to VOP_SPECSTRATEGY has not yet happened. Handle
the request just like we always did, but first time called print
debugging information.

Apart up to two instances of console messages per boot, this amounts
to a glorified no-op commit.

If you get any of the messages on your console I would very much
like a copy of them mailed to phk@freebsd.org

resort the vnode ops list.

Don't try to be cute and save a call/return by implementing a degenerate
vrele() inline.

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 the standard vp interlock macros.

Remember to unlock the (optional) vnode in vfs_stdextattrctl(). Failing
to do this made the following script hang:

#!/bin/sh
set -ex

extattrctl start /tmp
extattrctl initattr 64 /tmp/EA00
extattrctl enable /tmp user ea00 /tmp/EA00
extattrctl showattr /tmp/EA00

if the filesystem backing /tmp did not support EAs.

The real solution is probably to have the extattrctl syscall do the
unlocking rather than depend on the filesystem to do it. Considering
that extattrctl is going to be made obsolete anyway, this has dogwash
priority.

Sponsored by: DARPA & NAI Labs.

- 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

- The default for lock, unlock, and islocked is now std* instead of no*.

Remove vfs_stdmount() and vfs_stdunmount(). They are not
really useful and are incompatible with nmount.

Remove a stale comment saying that the vnode lock must be the first
element in the structure pointed to by vp->v_data; the vnode lock
is now within the vnode structure itself.

Remove references to vm_zone.h and switch over to the new uma API.

Also, remove maxsockets. If you look carefully you'll notice that the old
zone allocator never honored this anyway.

Remove __P.

Add a flags parameter to VFS_VGET to pass through the desired
locking flags when acquiring a vnode. The immediate purpose is
to allow polling lock requests (LK_NOWAIT) needed by soft updates
to avoid deadlock when enlisting other processes to help with
the background cleanup. For the future it will allow the use of
shared locks for read access to vnodes. This change touches a
lot of files as it affects most filesystems within the system.
It has been well tested on FFS, loopback, and CD-ROM filesystems.
only lightly on the others, so if you find a problem there, please
let me (mckusick@mckusick.com) know.

Document all functions, global and static variables, and sysctls.
Includes some minor whitespace changes, and re-ordering to be able to document
properly (e.g, grouping of variables and the SYSCTL macro calls for them, where
the documentation has been added.)

Reviewed by: phk (but all errors are mine)

Fix incorrect double-termination of vm_object. When a vm_object is
terminated and flushes pending dirty pages it is possible for the
object to be ref'd (0->1) and then deref'd (1->0) during termination.
We do not terminate the object a second time.

Document vop_stdgetvobject() to explicitly allow it to be called without
the vnode interlock held (for upcoming sync_msync() and ffs_sync()
performance optimizations)

MFC after: 3 days

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

With Alfred's permission, remove vm_mtx in favor of a fine-grained approach
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.

Don't release the vm lock just to turn around and grab it again.

Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb

When calling poll() on a fd associated with a filesystem, let POLLIN/POLLOUT
behave identically to POLLRDNORM/POLLWRNORM.

Submitted by: bde
PR: 27287
merge after: 1 week

Fix return type of vop_stdputpages()

Noticed by: rwatson

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.

Revert consequences of changes to mount.h, part 2.

Requested by: bde

Move the netexport structure from the fs-specific mountstructure
to struct mount.

This makes the "struct netexport *" paramter to the vfs_export
and vfs_checkexport interface unneeded.

Consequently that all non-stacking filesystems can use
vfs_stdcheckexp().

At the same time, make it a pointer to a struct netexport
in struct mount, so that we can remove the bogus AF_MAX
and #include <net/radix.h> from <sys/mount.h>

Correct #includes to work with fixed sys/mount.h.

This patch removes the VOP_BWRITE() vector.

VOP_BWRITE() was a hack which made it possible for NFS client
side to use struct buf with non-bio backing.

This patch takes a more general approach and adds a bp->b_op
vector where more methods can be added.

The success of this patch depends on bp->b_op being initialized
all relevant places for some value of "relevant" which is not
easy to determine. For now the buffers have grown a b_magic
element which will make such issues a tiny bit easier to debug.

o Rename "namespace" argument to "attrnamespace" as namespace is a C++
reserved word.

Submitted by: jkh
Obtained from: TrustedBSD Project

o Change the API and ABI of the Extended Attribute kernel interfaces to
introduce a new argument, "namespace", rather than relying on a first-
character namespace indicator. This is in line with more recent
thinking on EA interfaces on various mailing lists, including the
posix1e, Linux acl-devel, and trustedbsd-discuss forums. Two namespaces
are defined by default, EXTATTR_NAMESPACE_SYSTEM and
EXTATTR_NAMESPACE_USER, where the primary distinction lies in the
access control model: user EAs are accessible based on the normal
MAC and DAC file/directory protections, and system attributes are
limited to kernel-originated or appropriately privileged userland
requests.

o These API changes occur at several levels: the namespace argument is
introduced in the extattr_{get,set}_file() system call interfaces,
at the vnode operation level in the vop_{get,set}extattr() interfaces,
and in the UFS extended attribute implementation. Changes are also
introduced in the VFS extattrctl() interface (system call, VFS,
and UFS implementation), where the arguments are modified to include
a namespace field, as well as modified to advoid direct access to
userspace variables from below the VFS layer (in the style of recent
changes to mount by adrian@FreeBSD.org). This required some cleanup
and bug fixing regarding VFS locks and the VFS interface, as a vnode
pointer may now be optionally submitted to the VFS_EXTATTRCTL()
call. Updated documentation for the VFS interface will be committed
shortly.

o In the near future, the auto-starting feature will be updated to
search two sub-directories to the ".attribute" directory in appropriate
file systems: "user" and "system" to locate attributes intended for
those namespaces, as the single filename is no longer sufficient
to indicate what namespace the attribute is intended for. Until this
is committed, all attributes auto-started by UFS will be placed in
the EXTATTR_NAMESPACE_SYSTEM namespace.

o The default POSIX.1e attribute names for ACLs and Capabilities have
been updated to no longer include the '$' in their filename. As such,
if you're using these features, you'll need to rename the attribute
backing files to the same names without '$' symbols in front.

o Note that these changes will require changes in userland, which will
be committed shortly. These include modifications to the extended
attribute utilities, as well as to libutil for new namespace
string conversion routines. Once the matching userland changes are
committed, a buildworld is recommended to update all the necessary
include files and verify that the kernel and userland environments
are in sync. Note: If you do not use extended attributes (most people
won't), upgrading is not imperative although since the system call
API has changed, the new userland extended attribute code will no longer
compile with old include files.

o Couple of minor cleanups while I'm there: make more code compilation
conditional on FFS_EXTATTR, which should recover a bit of space on
kernels running without EA's, as well as update copyright dates.

Obtained from: TrustedBSD Project

Added a dummy lookup vop. Specfs was broken by removing its dummy
lookup vop so that it defaulted to using vop_eopnotsupp for strange
lookups like the ones for open("/dev/null/", ...) and stat("/dev/null/",
...). This mainly caused the wrong errno to be returned by vfs syscalls
(EOPNOTSUPP is not in POSIX, and is not documented in connection with
specfs in open.2 and is not documented in stat.2 at all). Also, lookup
vops are apparently required to set *ap->a_vpp to NULL on error, but
vop_eopnotsupp is too broken to do this.

Change and clean the mutex lock interface.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)

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

Catch up to moving headers:
- machine/ipl.h -> sys/ipl.h
- machine/mutex.h -> sys/mutex.h

Convert lockmgr locks from using simple locks to using mutexes.

Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is no
longer needed.

Add a lock structure to vnode structure. Previously it was either allocated
separately (nfs, cd9660 etc) or keept as a first element of structure
referenced by v_data pointer(ffs). Such organization leads to known problems
with stacked filesystems.

From this point vop_no*lock*() functions maintain only interlock lock.
vop_std*lock*() functions maintain built-in v_lock structure using lockmgr().
vop_sharedlock() is compatible with vop_stdunlock(), but maintains a shared
lock on vnode.

If filesystem wishes to export lockmgr compatible lock, it can put an address
of this lock to v_vnlock field. This indicates that the upper filesystem
can take advantage of it and use single lock structure for entire (or part)
of stack of vnodes. This field shouldn't be examined or modified by VFS code
except for initialization purposes.

Reviewed in general by: mckusick

Add three new VOPs: VOP_CREATEVOBJECT, VOP_DESTROYVOBJECT and VOP_GETVOBJECT.
They will be used by nullfs and other stacked filesystems to support full
cache coherency.

Reviewed in general by: mckusick, dillon

Introduce vop_stdinactive() and make it the default if no vop_inactive
is declared.

Sort and prune a few vop_op[].

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

Complete the bio/buf divorce for all code below devfs::strategy

Exceptions:
Vinum untouched. This means that it cannot be compiled.
Greg Lehey is on the case.

CCD not converted yet, casts to struct buf (still safe)

atapi-cd casts to struct buf to examine B_PHYS

Move B_ERROR flag to b_ioflags and call it BIO_ERROR.

(Much of this done by script)

Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.

Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.

Add bio_queue field for struct bio aware disksort.

Address a lot of stylistic issues brought up by bde.

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.

Fix bde'isms in acl/extattr syscall interface, renaming syscalls to
prettier (?) names, adding some const's around here, et al.

Reviewed by: bde

Second pass commit to introduce new ACL and Extended Attribute system
calls, vnops, vfsops, both in /kern, and to individual file systems that
require a vfsop_ array entry.

Reviewed by: eivind

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

Make vop_panic() a little more informative.

Seperate the export check in VFS_FHTOVP, exports are now checked via
VFS_CHECKEXP.

Add fh(open|stat|stafs) syscalls to allow userland to query filesystems
based on (network) filehandle.

Obtained from: NetBSD

All unimplemented VFS ops now have entries in kern/vfs_default.c that return
reasonable defaults.

This avoids confusing and ugly casting to eopnotsupp or making dummy functions.
Bogus casting of filesystem sysctls to eopnotsupp() have been removed.

This should make *_vfsops.c more readable and reduce bloat.

Reviewed by: msmith, eivind
Approved by: phk
Tested by: Jeroen Ruigrok/Asmodai <asmodai@wxs.nl>

$Id$ -> $FreeBSD$

Add Id strings

The VFS/BIO subsystem contained a number of hacks in order to optimize
piecemeal, middle-of-file writes for NFS. These hacks have caused no
end of trouble, especially when combined with mmap(). I've removed
them. Instead, NFS will issue a read-before-write to fully
instantiate the struct buf containing the write. NFS does, however,
optimize piecemeal appends to files. For most common file operations,
you will not notice the difference. The sole remaining fragment in
the VFS/BIO system is b_dirtyoff/end, which NFS uses to avoid cache
coherency issues with read-merge-write style operations. NFS also
optimizes the write-covers-entire-buffer case by avoiding the
read-before-write. There is quite a bit of room for further
optimization in these areas.

The VM system marks pages fully-valid (AKA vm_page_t->valid =
VM_PAGE_BITS_ALL) in several places, most noteably in vm_fault. This
is not correct operation. The vm_pager_get_pages() code is now
responsible for marking VM pages all-valid. A number of VM helper
routines have been added to aid in zeroing-out the invalid portions of
a VM page prior to the page being marked all-valid. This operation is
necessary to properly support mmap(). The zeroing occurs most often
when dealing with file-EOF situations. Several bugs have been fixed
in the NFS subsystem, including bits handling file and directory EOF
situations and buf->b_flags consistancy issues relating to clearing
B_ERROR & B_INVAL, and handling B_DONE.

getblk() and allocbuf() have been rewritten. B_CACHE operation is now
formally defined in comments and more straightforward in
implementation. B_CACHE for VMIO buffers is based on the validity of
the backing store. B_CACHE for non-VMIO buffers is based simply on
whether the buffer is B_INVAL or not (B_CACHE set if B_INVAL clear,
and vise-versa). biodone() is now responsible for setting B_CACHE
when a successful read completes. B_CACHE is also set when a bdwrite()
is initiated and when a bwrite() is initiated. VFS VOP_BWRITE
routines (there are only two - nfs_bwrite() and bwrite()) are now
expected to set B_CACHE. This means that bowrite() and bawrite() also
set B_CACHE indirectly.

There are a number of places in the code which were previously using
buf->b_bufsize (which is DEV_BSIZE aligned) when they should have
been using buf->b_bcount. These have been fixed. getblk() now clears
B_DONE on return because the rest of the system is so bad about
dealing with B_DONE.

Major fixes to NFS/TCP have been made. A server-side bug could cause
requests to be lost by the server due to nfs_realign() overwriting
other rpc's in the same TCP mbuf chain. The server's kernel must be
recompiled to get the benefit of the fixes.

Submitted by: Matthew Dillon <dillon@apollo.backplane.com>

Added a used #include (don't depend on "vnode_if.h" including <sys/buf.h>).

Add 'options DEBUG_LOCKS', which stores extra information in struct
lock, and add some macros and function parameters to make sure that
the information get to the point where it can be put in the lock
structure.

While I'm here, add DEBUG_VFS_LOCKS to LINT.

Make the vnode opv vector construction fully dynamic. Previously we
leaked memory on each unload and were limited to items referenced in
the kernel copy of vnode_if.c. Now a kernel module is free to create
it's own VOP_FOO() routines and the rest of the system will happily
deal with it, including passthrough layers like union/umap/etc.

Have VFS_SET() call a common vfs_modevent() handler rather than
inline duplicating the common code all over the place.

Have VNODEOP_SET() have the vnodeops removed at unload time (assuming a
module) so that the vop_t ** vector is reclaimed.

Slightly adjust the vop_t ** vectors so that calling slot 0 is a panic
rather than a page fault. This could happen if VOP_something() was called
without *any* handlers being present anywhere (including in vfs_default.c).
slot 1 becomes the default vector for the vnodeop table.

TODO: reclaim zones on unload (eg: nfs code)

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>

As described by the submitter:

Reverse the VFS_VRELE patch. Reference counting of vnodes does not need
to be done per-fs. I noticed this while fixing vfs layering violations.
Doing reference counting in generic code is also the preference cited by
John Heidemann in recent discussions with him.

The implementation of alternative vnode management per-fs is still a valid
requirement for some filesystems but will be revisited sometime later,
most likely using a different framework.

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

This mega-commit is meant to fix numerous interrelated problems. There
has been some bitrot and incorrect assumptions in the vfs_bio code. These
problems have manifest themselves worse on NFS type filesystems, but can
still affect local filesystems under certain circumstances. Most of
the problems have involved mmap consistancy, and as a side-effect broke
the vfs.ioopt code. This code might have been committed seperately, but
almost everything is interrelated.

1) Allow (pmap_object_init_pt) prefaulting of buffer-busy pages that
are fully valid.
2) Rather than deactivating erroneously read initial (header) pages in
kern_exec, we now free them.
3) Fix the rundown of non-VMIO buffers that are in an inconsistent
(missing vp) state.
4) Fix the disassociation of pages from buffers in brelse. The previous
code had rotted and was faulty in a couple of important circumstances.
5) Remove a gratuitious buffer wakeup in vfs_vmio_release.
6) Remove a crufty and currently unused cluster mechanism for VBLK
files in vfs_bio_awrite. When the code is functional, I'll add back
a cleaner version.
7) The page busy count wakeups assocated with the buffer cache usage were
incorrectly cleaned up in a previous commit by me. Revert to the
original, correct version, but with a cleaner implementation.
8) The cluster read code now tries to keep data associated with buffers
more aggressively (without breaking the heuristics) when it is presumed
that the read data (buffers) will be soon needed.
9) Change to filesystem lockmgr locks so that they use LK_NOPAUSE. The
delay loop waiting is not useful for filesystem locks, due to the
length of the time intervals.
10) Correct and clean-up spec_getpages.
11) Implement a fully functional nfs_getpages, nfs_putpages.
12) Fix nfs_write so that modifications are coherent with the NFS data on
the server disk (at least as well as NFS seems to allow.)
13) Properly support MS_INVALIDATE on NFS.
14) Properly pass down MS_INVALIDATE to lower levels of the VM code from
vm_map_clean.
15) Better support the notion of pages being busy but valid, so that
fewer in-transit waits occur. (use p->busy more for pageouts instead
of PG_BUSY.) Since the page is fully valid, it is still usable for
reads.
16) It is possible (in error) for cached pages to be busy. Make the
page allocation code handle that case correctly. (It should probably
be a printf or panic, but I want the system to handle coding errors
robustly. I'll probably add a printf.)
17) Correct the design and usage of vm_page_sleep. It didn't handle
consistancy problems very well, so make the design a little less
lofty. After vm_page_sleep, if it ever blocked, it is still important
to relookup the page (if the object generation count changed), and
verify it's status (always.)
18) In vm_pageout.c, vm_pageout_clean had rotted, so clean that up.
19) Push the page busy for writes and VM_PROT_READ into vm_pageout_flush.
20) Fix vm_pager_put_pages and it's descendents to support an int flag
instead of a boolean, so that we can pass down the invalidate bit.

The intent is to get rid of WILLRELE in vnode_if.src by making
a complement to all ops that return a vpp, VFS_VRELE. This is
initially only for file systems that implement the following ops
that do a WILLRELE:

vop_create, vop_whiteout, vop_mknod, vop_remove, vop_link,
vop_rename, vop_mkdir, vop_rmdir, vop_symlink

This is initial DNA that doesn't do anything yet. VFS_VRELE is
implemented but not called.

A default vfs_vrele was created for fs implementations that use the
standard vnode management routines.

VFS_VRELE implementations were made for the following file systems:

Standard (vfs_vrele)
ffs mfs nfs msdosfs devfs ext2fs

Custom
union umapfs

Just EOPNOTSUPP
fdesc procfs kernfs portal cd9660

These implementations may change as VOP changes are implemented.

In the next phase, in the vop implementations calls to vrele and the vrele
part of vput will be moved to the top layer vfs_vnops and made visible
to all layers. vput will be replaced by unlock in these cases. Unlocking
will still be done in the per fs layer but the refcount decrement will be
triggered at the top because it doesn't hurt to hold a vnode reference a
little longer. This will have minimal impact on the structure of the
existing code.

This will only be done for vnode arguments that are released by the various
fs vop implementations.

Wider use of VFS_VRELE will likely require restructuring of the code.

Reviewed by: phk, dyson, terry et. al.
Submitted by: Michael Hancock <michaelh@cet.co.jp>

Make our v_usecount vnode reference count work identically to the
original BSD code. The association between the vnode and the vm_object
no longer includes reference counts. The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.

When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also. The two "objects" are now
more intimately related, and so the interactions are now much less
complex.

When vnodes are now normally placed onto the free queue with an object still
attached. The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code. There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.

A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.

Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.

Revert poll() for UFS files to traditional behavior where polling for read-
or writability always returns true. This works around bugs in netscape and
squid, at a minimum.

Add support for poll(2) on files. vop_nopoll() now returns POLLNVAL
if one of the new poll types is requested; hopefully this will not break
any existing code. (This is done so that programs have a dependable
way of determining whether a filesystem supports the extended poll types
or not.)

The new poll types added are:

POLLWRITE - file contents may have been modified
POLLNLINK - file was linked, unlinked, or renamed
POLLATTRIB - file's attributes may have been changed
POLLEXTEND - file was extended

Note that the internal operation of poll() means that it is impossible
for two processes to reliably poll for the same event (this could
be fixed but may not be worth it), so it is not possible to rewrite
`tail -f' to use poll at this time.

Don't include <sys/lock.h> in headers when only `struct simplelock' is
required. Fixed everything that depended on the pollution.

Removed an unused #include.

Fixed a style bug (one of many KNF breakages in vfs_subr.c moved here).

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.

Simplify the lease_check stuff.

Make a set of VOP standard lock, unlock & islocked VOP operators, which
depend on the lock being located at vp->v_data. Saves 3x3 identical
vop procs, more as the other filesystems becomes lock aware.

VFS clean up "hekto commit"

1. Add defaults for more VOPs
VOP_LOCK vop_nolock
VOP_ISLOCKED vop_noislocked
VOP_UNLOCK vop_nounlock
and remove direct reference in filesystems.

2. Rename the nfsv2 vnop tables to improve sorting order.

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!!!)

Oops. forgot the blasted cvs add.

Pointed hat sent from: Karl Denninger <karl@Mcs.Net>