Move the include of <sys/malloc.h> to where it's truly needed.

follow the steps of Andrew Doran (ad) commit and fix more s/loose/lose/ typos.
also s/beyound/beyond/ and few others along the way, mainly in comments.

Overhaul of the EVFILT_VNODE kevent(2) filter:

- Centralize vnode kevent handling in the VOP_*() wrappers, rather than
forcing each individual file system to deal with it (except VOP_RENAME(),
because VOP_RENAME() is a mess and we currently have 2 different ways
of handling it; at least it's reasonably well-centralized in the "new"
way).
- Add support for NOTE_OPEN, NOTE_CLOSE, NOTE_CLOSE_WRITE, and NOTE_READ,
compatible with the same events in FreeBSD.
- Track which kevent notifications clients are interested in receiving
to avoid doing work for events no one cares about (avoiding, e.g.
taking locks and traversing the klist to send a NOTE_WRITE when
someone is merely watching for a file to be deleted, for example).

In support of the above:

- Add support in vnode_if.sh for specifying PRE- and POST-op handlers,
to be invoked before and after vop_pre() and vop_post(), respectively.
Basic idea from FreeBSD, but implemented differently.
- Add support in vnode_if.sh for specifying CONTEXT fields in the
vop_*_args structures. These context fields are used to convey information
between the file system VOP function and the VOP wrapper, but do not
occupy an argument slot in the VOP_*() call itself. These context fields
are initialized and subsequently interpreted by PRE- and POST-op handlers.
- Version VOP_REMOVE(), uses the a context field for the file system to report
back the resulting link count of the target vnode. Return this in tmpfs,
udf, nfs, chfs, ext2fs, lfs, and ufs.

NetBSD 9.99.92.

VFS_VGET(), VFS_ROOT(), VFS_FHTOVP(): give them a "int lktype" argument, to
allow us to get shared locks (or no lock) on the returned vnode. Matches
FreeBSD.

branches: 1.12.20; 1.12.26;
Revert previous, it is actually needed. (builds are failing)

Do not uselessly include <sys/malloc.h>.

branches: 1.10.4; 1.10.8; 1.10.12;
Remove udf_node * as state variables and add the loop invariants UFS and tmpfs
carry to make it easier to debug.

First step in rewriting the genealogy case

udf_gro_genealogy() : source and destination should never be the same on call,
KASSERT it instead of checking for it.

vp is used, so don't (void) it

Rework udf_gro_rename() to be more linear instead of nesting if/else
branching.

In case there is trouble determining the number of entries in a directory,
return its not empty to be on the safe side.

Resort to the easiest way to check if a directory is deleted: the flag that
tells that there is no FID (dirent) pointing to it anymore.

Small cleanup

Remove the dirent checks and references. UDF doesn't need/use them on rename
so just to make sure, we remove all references/checks to not trigger bugs
thats are not really ours.

Implement udf_rename() using the new genfs_rename() framework.

Fixes PR kern/47986

follow the steps of Andrew Doran (ad) commit and fix more s/loose/lose/ typos.
also s/beyound/beyond/ and few others along the way, mainly in comments.

Overhaul of the EVFILT_VNODE kevent(2) filter:

- Centralize vnode kevent handling in the VOP_*() wrappers, rather than
forcing each individual file system to deal with it (except VOP_RENAME(),
because VOP_RENAME() is a mess and we currently have 2 different ways
of handling it; at least it's reasonably well-centralized in the "new"
way).
- Add support for NOTE_OPEN, NOTE_CLOSE, NOTE_CLOSE_WRITE, and NOTE_READ,
compatible with the same events in FreeBSD.
- Track which kevent notifications clients are interested in receiving
to avoid doing work for events no one cares about (avoiding, e.g.
taking locks and traversing the klist to send a NOTE_WRITE when
someone is merely watching for a file to be deleted, for example).

In support of the above:

- Add support in vnode_if.sh for specifying PRE- and POST-op handlers,
to be invoked before and after vop_pre() and vop_post(), respectively.
Basic idea from FreeBSD, but implemented differently.
- Add support in vnode_if.sh for specifying CONTEXT fields in the
vop_*_args structures. These context fields are used to convey information
between the file system VOP function and the VOP wrapper, but do not
occupy an argument slot in the VOP_*() call itself. These context fields
are initialized and subsequently interpreted by PRE- and POST-op handlers.
- Version VOP_REMOVE(), uses the a context field for the file system to report
back the resulting link count of the target vnode. Return this in tmpfs,
udf, nfs, chfs, ext2fs, lfs, and ufs.

NetBSD 9.99.92.

VFS_VGET(), VFS_ROOT(), VFS_FHTOVP(): give them a "int lktype" argument, to
allow us to get shared locks (or no lock) on the returned vnode. Matches
FreeBSD.

branches: 1.12.20; 1.12.26;
Revert previous, it is actually needed. (builds are failing)

Do not uselessly include <sys/malloc.h>.

branches: 1.10.4; 1.10.8; 1.10.12;
Remove udf_node * as state variables and add the loop invariants UFS and tmpfs
carry to make it easier to debug.

First step in rewriting the genealogy case

udf_gro_genealogy() : source and destination should never be the same on call,
KASSERT it instead of checking for it.

vp is used, so don't (void) it

Rework udf_gro_rename() to be more linear instead of nesting if/else
branching.

In case there is trouble determining the number of entries in a directory,
return its not empty to be on the safe side.

Resort to the easiest way to check if a directory is deleted: the flag that
tells that there is no FID (dirent) pointing to it anymore.

Small cleanup

Remove the dirent checks and references. UDF doesn't need/use them on rename
so just to make sure, we remove all references/checks to not trigger bugs
thats are not really ours.

Implement udf_rename() using the new genfs_rename() framework.

Fixes PR kern/47986

Overhaul of the EVFILT_VNODE kevent(2) filter:

- Centralize vnode kevent handling in the VOP_*() wrappers, rather than
forcing each individual file system to deal with it (except VOP_RENAME(),
because VOP_RENAME() is a mess and we currently have 2 different ways
of handling it; at least it's reasonably well-centralized in the "new"
way).
- Add support for NOTE_OPEN, NOTE_CLOSE, NOTE_CLOSE_WRITE, and NOTE_READ,
compatible with the same events in FreeBSD.
- Track which kevent notifications clients are interested in receiving
to avoid doing work for events no one cares about (avoiding, e.g.
taking locks and traversing the klist to send a NOTE_WRITE when
someone is merely watching for a file to be deleted, for example).

In support of the above:

- Add support in vnode_if.sh for specifying PRE- and POST-op handlers,
to be invoked before and after vop_pre() and vop_post(), respectively.
Basic idea from FreeBSD, but implemented differently.
- Add support in vnode_if.sh for specifying CONTEXT fields in the
vop_*_args structures. These context fields are used to convey information
between the file system VOP function and the VOP wrapper, but do not
occupy an argument slot in the VOP_*() call itself. These context fields
are initialized and subsequently interpreted by PRE- and POST-op handlers.
- Version VOP_REMOVE(), uses the a context field for the file system to report
back the resulting link count of the target vnode. Return this in tmpfs,
udf, nfs, chfs, ext2fs, lfs, and ufs.

NetBSD 9.99.92.

VFS_VGET(), VFS_ROOT(), VFS_FHTOVP(): give them a "int lktype" argument, to
allow us to get shared locks (or no lock) on the returned vnode. Matches
FreeBSD.

branches: 1.12.20; 1.12.26;
Revert previous, it is actually needed. (builds are failing)

Do not uselessly include <sys/malloc.h>.

branches: 1.10.4; 1.10.8; 1.10.12;
Remove udf_node * as state variables and add the loop invariants UFS and tmpfs
carry to make it easier to debug.

First step in rewriting the genealogy case

udf_gro_genealogy() : source and destination should never be the same on call,
KASSERT it instead of checking for it.

vp is used, so don't (void) it

Rework udf_gro_rename() to be more linear instead of nesting if/else
branching.

In case there is trouble determining the number of entries in a directory,
return its not empty to be on the safe side.

Resort to the easiest way to check if a directory is deleted: the flag that
tells that there is no FID (dirent) pointing to it anymore.

Small cleanup

Remove the dirent checks and references. UDF doesn't need/use them on rename
so just to make sure, we remove all references/checks to not trigger bugs
thats are not really ours.

Implement udf_rename() using the new genfs_rename() framework.

Fixes PR kern/47986

VFS_VGET(), VFS_ROOT(), VFS_FHTOVP(): give them a "int lktype" argument, to
allow us to get shared locks (or no lock) on the returned vnode. Matches
FreeBSD.

branches: 1.12.26;
Revert previous, it is actually needed. (builds are failing)

Do not uselessly include <sys/malloc.h>.

branches: 1.10.4; 1.10.8; 1.10.12;
Remove udf_node * as state variables and add the loop invariants UFS and tmpfs
carry to make it easier to debug.

First step in rewriting the genealogy case

udf_gro_genealogy() : source and destination should never be the same on call,
KASSERT it instead of checking for it.

vp is used, so don't (void) it

Rework udf_gro_rename() to be more linear instead of nesting if/else
branching.

In case there is trouble determining the number of entries in a directory,
return its not empty to be on the safe side.

Resort to the easiest way to check if a directory is deleted: the flag that
tells that there is no FID (dirent) pointing to it anymore.

Small cleanup

Remove the dirent checks and references. UDF doesn't need/use them on rename
so just to make sure, we remove all references/checks to not trigger bugs
thats are not really ours.

Implement udf_rename() using the new genfs_rename() framework.

Fixes PR kern/47986