Use the module subsystem's ability to process SYSCTL_SETUP() entries to
automate installation of sysctl nodes.

Note that there are still a number of device and pseudo-device modules
that create entries tied to individual device units, rather than to the
module itself. These are not changed.

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: 1.56.20;
Add generic genfs_suspendctl() and use it for all file systems.
Layered file systems need work.

branches: 1.55.2; 1.55.4; 1.55.6;
Revert previous; it does not work with COMPAT_BSDPTY, screen(1) fails because
it does a TIOCPTSNAME immediately after opening ptmx and finds an old style pty.

From Ilia Zykov:
- correct some incorrect comments
- add XXX warning
- increase security by activating when get the slave
- make pty_vn_open() private to tty_ptm.c

Change ptyfs to vcache.
- Use (type, minor) as key.
- Change ptyfs_allocvp to return a referenced vnode and lock where needed.
- Remove unneeded vnode backpointer ptyfs_vnode.
- Keep a single hashlist for pty nodes to make their attributes persistent.

OK: Christos Zoulas

Overflow if *data_len == OSIZE and args->version >= PTYFS_ARGSVERSION.

Sent on tech-kern@, ok christos@

- Add a map of active controlling ptys per mount and no longer abuse
the vnode lifecycle.
- No longer set "recycle" on VOP_INACTIVE().
- Make ptyfs_used_get() private to ptyfs_subr.c
- Stop copying device attributes from traditional ptys on first allocation.
- Remove unneeded argument "lwp" from ptyfs_allocvp() and ptyfs_free_get().

OK: Christos Zoulas

branches: 1.50.2;
An (un)privileged user can easily make the kernel dereference a NULL
pointer.

The kernel allows 'data' to be NULL; it's the fs's responsibility to
ensure that it isn't NULL (if the fs actually needs data).

ok christos@

branches: 1.49.2;
Handle multiple ptyfs mounts with different chroots. ptys opened in one
chroot are only visible in that chroot.

From Ilya Zykov:
- ifdef out some code that is only used for NO_DEV_PTM
- pass the mountpoint instead of the ptm structure to the implementation
dependent (ptyfs or bsdpty) functions.
- add a function to return the correct ptyfs mountpoint for the current lwp

Change all vfsops to use C99 designated initializers.

No functional changes intended.

- return an error if we could not get the pts pathname
- correct getting pathname if the mount point inside a chroot
(Ilya Zykov)

Ensure that the top level sysctl nodes (kern, vfs, net, ...) exist before
the sysctl link sets are processed, and remove redundancy.

Shaves >13kB off of an amd64 GENERIC, not to mention >1k duplicate
lines of code.

branches: 1.44.2;
let us get mounted multiple times.

Always do the chroot filename mapping; it is pointless not to do it.

branches: 1.42.12; 1.42.18; 1.42.20; 1.42.22;
The VATTR_NULL/VREF/VHOLD/HOLDRELE() macros lost their will to live
years ago when the kernel was modified to not alter ABI based on
DIAGNOSTIC, and now just call the respective function interfaces
(in lowercase). Plenty of mix'n match upper/lowercase has creeped
into the tree since then. Nuke the macros and convert all callsites
to lowercase.

no functional change

Introduce genfs_statvfs() as pretty much a no-info statvfs and
convert several pseudo file systems to use it.

Fix old userland compat.

Add a chroot flag, so that ptyfs can be mounted in a chrooted environment.
XXX: This is a hack, in reality we should allow multiple ptyfs mounts.

branches: 1.38.2;
merge christos-time_t

branches: 1.37.2; 1.37.4; 1.37.6; 1.37.14; 1.37.18;
Remove logic to compute relative pathes to chroots. It breaks the
default case of ptyfs mounted under /dev/pts as any chroot would get
/%d as slave names. This allows null mounts of ptyfs to work.
To allow pty allocation from within chroots, either no ptyfs must be
mounted or a null mount exist.

branches: 1.36.2;
Create sysctl entries during module initialisation and destroy them
appropriately.

Many of these file systems are now ready for modularisation.

branches: 1.35.2;
mnt_data is a pointer, set it to NULL not 0 when we're finished with it.

Use the correct malloc type when free()ing the ptyfs mount structure.
Fixes the "free 2: inuse 0, probable double free" panic when using ptyfs
and KMEMSTATS.

Convert file systems to dynamically attach with the new module interface.
Make VFS hooks dynamic while we're here and say farewell to VFS_ATTACH and
VFS_HOOKS_ATTACH linksets.

As a consequence, most of the file systems can now be loaded as new style
modules.

Quick sanity check by ad@.

branches: 1.32.2;
PR kern/38057 ffs makes assuptions about devvp file system
PR kern/33406 softdeps get stuck in endless loop

Introduce VFS_FSYNC() and call it when syncing a block device, if it
has a mounted file system.

branches: 1.31.6; 1.31.8; 1.31.10;
Fix some race conditions in rename.
Introduce a per-FS rename lock and new vfsops to manipulate it.
Get this lock while renaming. Also add another relookup() in do_sys_rename,
which is a hack to kludge around some of the worst deficiencies of
ufs_rename.
reviewed-by: pooka (and an earlier rev by ad)
posted on tech-kern with no objections.

Remove the "struct lwp *" argument from all VFS and VOP interfaces.
The general trend is to remove it from all kernel interfaces and
this is a start. In case the calling lwp is desired, curlwp should
be used.

quick consensus on tech-kern

branches: 1.29.4;
Avoid stack allocation of large dirent structures in foo_readdir().

branches: 1.28.2; 1.28.4; 1.28.6; 1.28.8;
* nuke the nameidata parameter from VFS_MOUNT(). Nobody on tech-kern
knew what it was supposed to be used for and wrstuden gave a go-ahead
* while rototilling, convert file systems which went easily to
use VFS_PROTOS() instead of manually prototyping the methods

Use eopnotsupp() instead of vfs_stdsuspendctl() and retire the latter.

branches: 1.26.2;
Make set_statvfs_info() take a parameter for the vfs name instead
of always retrieving it from mp->mnt_op->vfs_name

christos ok

Change the VFS_MOUNT() interface so that the 'data' buffer passed to the
fs code is a kernel buffer, pass though the length of the buffer as well.
Since the length of the userspace buffer isn'it (yet) passed through the mount
system call, add a field to the vfsops structure containing the default length.
Split sys_mount() for calls from compat code.
Ride one of the recent kernel version changes - old fs LKMs will load, but
sys_mount() will reject any attempt to use them.

Using POOL_INIT here makes no sense, since file systems always have
an init method. So get rid of it and #ifdef _LKM and just always
init in the init method. Give malloc types the same treatment.
Makes file systems nicer to work with in linksetless environments
and fixes a few LKM discrepancies.

branches: 1.23.6; 1.23.8;
New file system suspension API to replace vn_start_write and vn_finished_write.
The suspension helpers are now put into file system specific operations.
This means every file system not supporting these helpers cannot be suspended
and therefore snapshots are no longer possible.

Implemented for file systems of type ffs.

The new API is enabled on a kernel option NEWVNGATE. This option is
not enabled by default in any kernel config.

Presented and discussed on tech-kern with much input from
Bill Studenmund <wrstuden@netbsd.org> and YAMAMOTO Takashi <yamt@netbsd.org>.

Welcome to 4.99.9 (new vfs op vfs_suspendctl).

a smorgasbord of improvements to vnode locking and path lookup:
- LOCKPARENT is no longer relevant for lookup(), relookup() or VOP_LOOKUP().
these now always return the parent vnode locked. namei() works as before.
lookup() and various other paths no longer acquire vnode locks in the
wrong order via vrele(). fixes PR 32535.
as a nice side effect, path lookup is also up to 25% faster.
- the above allows us to get rid of PDIRUNLOCK.
- also get rid of WANTPARENT (just use LOCKPARENT and unlock it).
- remove an assumption in layer_node_find() that all file systems implement
a recursive VOP_LOCK() (unionfs doesn't).
- require that all file systems supply vfs_vptofh and vfs_fhtovp routines.
fill in eopnotsupp() for file systems that don't support being exported
and remove the checks for NULL. (layerfs calls these without checking.)
- in union_lookup1(), don't change refcounts in the ISDOTDOT case, just
adjust which vnode is locked. fixes PR 33374.
- apply fixes for ufs_rename() from ufs_vnops.c rev. 1.61 to ext2fs_rename().

branches: 1.21.2;
__unused removal on arguments; approved by core.

- sprinkle __unused on function decls.
- fix a couple of unused bugs
- no more -Wno-unused for i386

branches: 1.19.2; 1.19.4;
add missing initializers

Use the LWP cached credentials where sane.

Make this compile again.

Don't allocate too much stuff on the stack.

branches: 1.15.4;
integrate kauth.

Do the count check after we process getargs.

Strip the chrooted portion of the path from the reported pty path. Reported
and tested by Lasse Kliemann. Thanks!

branches: 1.12.4; 1.12.6; 1.12.8; 1.12.10; 1.12.12;
merge ktrace-lwp.

use a counter to prevent from mounting ptyfs twice. Using save_ptm is not
good enough, because if we don't have COMPAT_BSDPTY, then it will stay NULL.

Move the duplicate mount check sooner, and fix a leak.

Apply the NFS exports list rototill patch:

- Remove all NFS related stuff from file system specific code.
- Drop the vfs_checkexp hook and generalize it in the new nfs_check_export
function, thus removing redundancy from all file systems.
- Move all NFS export-related stuff from kern/vfs_subr.c to the new
file sys/nfs/nfs_export.c. The former was becoming large and its code
is always compiled, regardless of the build options. Using the latter,
the code is only compiled in when NFSSERVER is enabled. While doing this,
also make some functions in nfs_subs.c conditional to NFSSERVER.
- Add a new command in nfssvc(2), called NFSSVC_SETEXPORTSLIST, that takes a
path and a set of export entries. At the moment it can only clear the
exports list or append entries, one by one, but it is done in a way that
allows setting the whole set of entries atomically in the future (see the
comment in mountd_set_exports_list or in doc/TODO).
- Change mountd(8) to use the nfssvc(2) system call instead of mount(2) so
that it becomes file system agnostic. In fact, all this whole thing was
done to remove a 'XXX' block from this utility!
- Change the mount*, newfs and fsck* userland utilities to not deal with NFS
exports initialization; done internally by the kernel when initializing
the NFS support for each file system.
- Implement an interface for VFS (called VFS hooks) so that several kernel
subsystems can run arbitrary code upon receipt of specific VFS events.
At the moment, this only provides support for unmount and is used to
destroy NFS exports lists from the file systems being unmounted, though it
has room for extension.

Thanks go to yamt@, chs@, thorpej@, wrstuden@ and others for their comments
and advice in the development of this patch.

branches: 1.8.2;
- rename variables to avoid shadowing.
- add a few const.

Remove compat code that hard-codes default group and mode for pty creation.
Hi Matt!

- Define a VFS_ATTACH() macro that places a reference to a vfsops structure
into the "vfsops" link set.
- Use VFS_ATTACH() where vfsops are declared for individual file systems.
- In vfsinit(), traverse the "vfsops" link set, rather than vfs_list_initial[].

nuke trailing whitespace

branches: 1.4.2; 1.4.4;
make this compile again; hi potr

Add pty group and mode settings.

branches: 1.2.2;
update #include path to fs/ptyfs/

move ptyfs off sys/miscfs/ptyfs/ to sys/fs/ptyfs/

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: 1.56.20;
Add generic genfs_suspendctl() and use it for all file systems.
Layered file systems need work.

branches: 1.55.2; 1.55.4; 1.55.6;
Revert previous; it does not work with COMPAT_BSDPTY, screen(1) fails because
it does a TIOCPTSNAME immediately after opening ptmx and finds an old style pty.

From Ilia Zykov:
- correct some incorrect comments
- add XXX warning
- increase security by activating when get the slave
- make pty_vn_open() private to tty_ptm.c

Change ptyfs to vcache.
- Use (type, minor) as key.
- Change ptyfs_allocvp to return a referenced vnode and lock where needed.
- Remove unneeded vnode backpointer ptyfs_vnode.
- Keep a single hashlist for pty nodes to make their attributes persistent.

OK: Christos Zoulas

Overflow if *data_len == OSIZE and args->version >= PTYFS_ARGSVERSION.

Sent on tech-kern@, ok christos@

- Add a map of active controlling ptys per mount and no longer abuse
the vnode lifecycle.
- No longer set "recycle" on VOP_INACTIVE().
- Make ptyfs_used_get() private to ptyfs_subr.c
- Stop copying device attributes from traditional ptys on first allocation.
- Remove unneeded argument "lwp" from ptyfs_allocvp() and ptyfs_free_get().

OK: Christos Zoulas

branches: 1.50.2;
An (un)privileged user can easily make the kernel dereference a NULL
pointer.

The kernel allows 'data' to be NULL; it's the fs's responsibility to
ensure that it isn't NULL (if the fs actually needs data).

ok christos@

branches: 1.49.2;
Handle multiple ptyfs mounts with different chroots. ptys opened in one
chroot are only visible in that chroot.

From Ilya Zykov:
- ifdef out some code that is only used for NO_DEV_PTM
- pass the mountpoint instead of the ptm structure to the implementation
dependent (ptyfs or bsdpty) functions.
- add a function to return the correct ptyfs mountpoint for the current lwp

Change all vfsops to use C99 designated initializers.

No functional changes intended.

- return an error if we could not get the pts pathname
- correct getting pathname if the mount point inside a chroot
(Ilya Zykov)

Ensure that the top level sysctl nodes (kern, vfs, net, ...) exist before
the sysctl link sets are processed, and remove redundancy.

Shaves >13kB off of an amd64 GENERIC, not to mention >1k duplicate
lines of code.

branches: 1.44.2;
let us get mounted multiple times.

Always do the chroot filename mapping; it is pointless not to do it.

branches: 1.42.12; 1.42.18; 1.42.20; 1.42.22;
The VATTR_NULL/VREF/VHOLD/HOLDRELE() macros lost their will to live
years ago when the kernel was modified to not alter ABI based on
DIAGNOSTIC, and now just call the respective function interfaces
(in lowercase). Plenty of mix'n match upper/lowercase has creeped
into the tree since then. Nuke the macros and convert all callsites
to lowercase.

no functional change

Introduce genfs_statvfs() as pretty much a no-info statvfs and
convert several pseudo file systems to use it.

Fix old userland compat.

Add a chroot flag, so that ptyfs can be mounted in a chrooted environment.
XXX: This is a hack, in reality we should allow multiple ptyfs mounts.

branches: 1.38.2;
merge christos-time_t

branches: 1.37.2; 1.37.4; 1.37.6; 1.37.14; 1.37.18;
Remove logic to compute relative pathes to chroots. It breaks the
default case of ptyfs mounted under /dev/pts as any chroot would get
/%d as slave names. This allows null mounts of ptyfs to work.
To allow pty allocation from within chroots, either no ptyfs must be
mounted or a null mount exist.

branches: 1.36.2;
Create sysctl entries during module initialisation and destroy them
appropriately.

Many of these file systems are now ready for modularisation.

branches: 1.35.2;
mnt_data is a pointer, set it to NULL not 0 when we're finished with it.

Use the correct malloc type when free()ing the ptyfs mount structure.
Fixes the "free 2: inuse 0, probable double free" panic when using ptyfs
and KMEMSTATS.

Convert file systems to dynamically attach with the new module interface.
Make VFS hooks dynamic while we're here and say farewell to VFS_ATTACH and
VFS_HOOKS_ATTACH linksets.

As a consequence, most of the file systems can now be loaded as new style
modules.

Quick sanity check by ad@.

branches: 1.32.2;
PR kern/38057 ffs makes assuptions about devvp file system
PR kern/33406 softdeps get stuck in endless loop

Introduce VFS_FSYNC() and call it when syncing a block device, if it
has a mounted file system.

branches: 1.31.6; 1.31.8; 1.31.10;
Fix some race conditions in rename.
Introduce a per-FS rename lock and new vfsops to manipulate it.
Get this lock while renaming. Also add another relookup() in do_sys_rename,
which is a hack to kludge around some of the worst deficiencies of
ufs_rename.
reviewed-by: pooka (and an earlier rev by ad)
posted on tech-kern with no objections.

Remove the "struct lwp *" argument from all VFS and VOP interfaces.
The general trend is to remove it from all kernel interfaces and
this is a start. In case the calling lwp is desired, curlwp should
be used.

quick consensus on tech-kern

branches: 1.29.4;
Avoid stack allocation of large dirent structures in foo_readdir().

branches: 1.28.2; 1.28.4; 1.28.6; 1.28.8;
* nuke the nameidata parameter from VFS_MOUNT(). Nobody on tech-kern
knew what it was supposed to be used for and wrstuden gave a go-ahead
* while rototilling, convert file systems which went easily to
use VFS_PROTOS() instead of manually prototyping the methods

Use eopnotsupp() instead of vfs_stdsuspendctl() and retire the latter.

branches: 1.26.2;
Make set_statvfs_info() take a parameter for the vfs name instead
of always retrieving it from mp->mnt_op->vfs_name

christos ok

Change the VFS_MOUNT() interface so that the 'data' buffer passed to the
fs code is a kernel buffer, pass though the length of the buffer as well.
Since the length of the userspace buffer isn'it (yet) passed through the mount
system call, add a field to the vfsops structure containing the default length.
Split sys_mount() for calls from compat code.
Ride one of the recent kernel version changes - old fs LKMs will load, but
sys_mount() will reject any attempt to use them.

Using POOL_INIT here makes no sense, since file systems always have
an init method. So get rid of it and #ifdef _LKM and just always
init in the init method. Give malloc types the same treatment.
Makes file systems nicer to work with in linksetless environments
and fixes a few LKM discrepancies.

branches: 1.23.6; 1.23.8;
New file system suspension API to replace vn_start_write and vn_finished_write.
The suspension helpers are now put into file system specific operations.
This means every file system not supporting these helpers cannot be suspended
and therefore snapshots are no longer possible.

Implemented for file systems of type ffs.

The new API is enabled on a kernel option NEWVNGATE. This option is
not enabled by default in any kernel config.

Presented and discussed on tech-kern with much input from
Bill Studenmund <wrstuden@netbsd.org> and YAMAMOTO Takashi <yamt@netbsd.org>.

Welcome to 4.99.9 (new vfs op vfs_suspendctl).

a smorgasbord of improvements to vnode locking and path lookup:
- LOCKPARENT is no longer relevant for lookup(), relookup() or VOP_LOOKUP().
these now always return the parent vnode locked. namei() works as before.
lookup() and various other paths no longer acquire vnode locks in the
wrong order via vrele(). fixes PR 32535.
as a nice side effect, path lookup is also up to 25% faster.
- the above allows us to get rid of PDIRUNLOCK.
- also get rid of WANTPARENT (just use LOCKPARENT and unlock it).
- remove an assumption in layer_node_find() that all file systems implement
a recursive VOP_LOCK() (unionfs doesn't).
- require that all file systems supply vfs_vptofh and vfs_fhtovp routines.
fill in eopnotsupp() for file systems that don't support being exported
and remove the checks for NULL. (layerfs calls these without checking.)
- in union_lookup1(), don't change refcounts in the ISDOTDOT case, just
adjust which vnode is locked. fixes PR 33374.
- apply fixes for ufs_rename() from ufs_vnops.c rev. 1.61 to ext2fs_rename().

branches: 1.21.2;
__unused removal on arguments; approved by core.

- sprinkle __unused on function decls.
- fix a couple of unused bugs
- no more -Wno-unused for i386

branches: 1.19.2; 1.19.4;
add missing initializers

Use the LWP cached credentials where sane.

Make this compile again.

Don't allocate too much stuff on the stack.

branches: 1.15.4;
integrate kauth.

Do the count check after we process getargs.

Strip the chrooted portion of the path from the reported pty path. Reported
and tested by Lasse Kliemann. Thanks!

branches: 1.12.4; 1.12.6; 1.12.8; 1.12.10; 1.12.12;
merge ktrace-lwp.

use a counter to prevent from mounting ptyfs twice. Using save_ptm is not
good enough, because if we don't have COMPAT_BSDPTY, then it will stay NULL.

Move the duplicate mount check sooner, and fix a leak.

Apply the NFS exports list rototill patch:

- Remove all NFS related stuff from file system specific code.
- Drop the vfs_checkexp hook and generalize it in the new nfs_check_export
function, thus removing redundancy from all file systems.
- Move all NFS export-related stuff from kern/vfs_subr.c to the new
file sys/nfs/nfs_export.c. The former was becoming large and its code
is always compiled, regardless of the build options. Using the latter,
the code is only compiled in when NFSSERVER is enabled. While doing this,
also make some functions in nfs_subs.c conditional to NFSSERVER.
- Add a new command in nfssvc(2), called NFSSVC_SETEXPORTSLIST, that takes a
path and a set of export entries. At the moment it can only clear the
exports list or append entries, one by one, but it is done in a way that
allows setting the whole set of entries atomically in the future (see the
comment in mountd_set_exports_list or in doc/TODO).
- Change mountd(8) to use the nfssvc(2) system call instead of mount(2) so
that it becomes file system agnostic. In fact, all this whole thing was
done to remove a 'XXX' block from this utility!
- Change the mount*, newfs and fsck* userland utilities to not deal with NFS
exports initialization; done internally by the kernel when initializing
the NFS support for each file system.
- Implement an interface for VFS (called VFS hooks) so that several kernel
subsystems can run arbitrary code upon receipt of specific VFS events.
At the moment, this only provides support for unmount and is used to
destroy NFS exports lists from the file systems being unmounted, though it
has room for extension.

Thanks go to yamt@, chs@, thorpej@, wrstuden@ and others for their comments
and advice in the development of this patch.

branches: 1.8.2;
- rename variables to avoid shadowing.
- add a few const.

Remove compat code that hard-codes default group and mode for pty creation.
Hi Matt!

- Define a VFS_ATTACH() macro that places a reference to a vfsops structure
into the "vfsops" link set.
- Use VFS_ATTACH() where vfsops are declared for individual file systems.
- In vfsinit(), traverse the "vfsops" link set, rather than vfs_list_initial[].

nuke trailing whitespace

branches: 1.4.2; 1.4.4;
make this compile again; hi potr

Add pty group and mode settings.

branches: 1.2.2;
update #include path to fs/ptyfs/

move ptyfs off sys/miscfs/ptyfs/ to sys/fs/ptyfs/

Add generic genfs_suspendctl() and use it for all file systems.
Layered file systems need work.

branches: 1.55.2; 1.55.4; 1.55.6;
Revert previous; it does not work with COMPAT_BSDPTY, screen(1) fails because
it does a TIOCPTSNAME immediately after opening ptmx and finds an old style pty.

From Ilia Zykov:
- correct some incorrect comments
- add XXX warning
- increase security by activating when get the slave
- make pty_vn_open() private to tty_ptm.c

Change ptyfs to vcache.
- Use (type, minor) as key.
- Change ptyfs_allocvp to return a referenced vnode and lock where needed.
- Remove unneeded vnode backpointer ptyfs_vnode.
- Keep a single hashlist for pty nodes to make their attributes persistent.

OK: Christos Zoulas

Overflow if *data_len == OSIZE and args->version >= PTYFS_ARGSVERSION.

Sent on tech-kern@, ok christos@

- Add a map of active controlling ptys per mount and no longer abuse
the vnode lifecycle.
- No longer set "recycle" on VOP_INACTIVE().
- Make ptyfs_used_get() private to ptyfs_subr.c
- Stop copying device attributes from traditional ptys on first allocation.
- Remove unneeded argument "lwp" from ptyfs_allocvp() and ptyfs_free_get().

OK: Christos Zoulas

branches: 1.50.2;
An (un)privileged user can easily make the kernel dereference a NULL
pointer.

The kernel allows 'data' to be NULL; it's the fs's responsibility to
ensure that it isn't NULL (if the fs actually needs data).

ok christos@

branches: 1.49.2;
Handle multiple ptyfs mounts with different chroots. ptys opened in one
chroot are only visible in that chroot.

From Ilya Zykov:
- ifdef out some code that is only used for NO_DEV_PTM
- pass the mountpoint instead of the ptm structure to the implementation
dependent (ptyfs or bsdpty) functions.
- add a function to return the correct ptyfs mountpoint for the current lwp

Change all vfsops to use C99 designated initializers.

No functional changes intended.

- return an error if we could not get the pts pathname
- correct getting pathname if the mount point inside a chroot
(Ilya Zykov)

Ensure that the top level sysctl nodes (kern, vfs, net, ...) exist before
the sysctl link sets are processed, and remove redundancy.

Shaves >13kB off of an amd64 GENERIC, not to mention >1k duplicate
lines of code.

branches: 1.44.2;
let us get mounted multiple times.

Always do the chroot filename mapping; it is pointless not to do it.

branches: 1.42.12; 1.42.18; 1.42.20; 1.42.22;
The VATTR_NULL/VREF/VHOLD/HOLDRELE() macros lost their will to live
years ago when the kernel was modified to not alter ABI based on
DIAGNOSTIC, and now just call the respective function interfaces
(in lowercase). Plenty of mix'n match upper/lowercase has creeped
into the tree since then. Nuke the macros and convert all callsites
to lowercase.

no functional change

Introduce genfs_statvfs() as pretty much a no-info statvfs and
convert several pseudo file systems to use it.

Fix old userland compat.

Add a chroot flag, so that ptyfs can be mounted in a chrooted environment.
XXX: This is a hack, in reality we should allow multiple ptyfs mounts.

branches: 1.38.2;
merge christos-time_t

branches: 1.37.2; 1.37.4; 1.37.6; 1.37.14; 1.37.18;
Remove logic to compute relative pathes to chroots. It breaks the
default case of ptyfs mounted under /dev/pts as any chroot would get
/%d as slave names. This allows null mounts of ptyfs to work.
To allow pty allocation from within chroots, either no ptyfs must be
mounted or a null mount exist.

branches: 1.36.2;
Create sysctl entries during module initialisation and destroy them
appropriately.

Many of these file systems are now ready for modularisation.

branches: 1.35.2;
mnt_data is a pointer, set it to NULL not 0 when we're finished with it.

Use the correct malloc type when free()ing the ptyfs mount structure.
Fixes the "free 2: inuse 0, probable double free" panic when using ptyfs
and KMEMSTATS.

Convert file systems to dynamically attach with the new module interface.
Make VFS hooks dynamic while we're here and say farewell to VFS_ATTACH and
VFS_HOOKS_ATTACH linksets.

As a consequence, most of the file systems can now be loaded as new style
modules.

Quick sanity check by ad@.

branches: 1.32.2;
PR kern/38057 ffs makes assuptions about devvp file system
PR kern/33406 softdeps get stuck in endless loop

Introduce VFS_FSYNC() and call it when syncing a block device, if it
has a mounted file system.

branches: 1.31.6; 1.31.8; 1.31.10;
Fix some race conditions in rename.
Introduce a per-FS rename lock and new vfsops to manipulate it.
Get this lock while renaming. Also add another relookup() in do_sys_rename,
which is a hack to kludge around some of the worst deficiencies of
ufs_rename.
reviewed-by: pooka (and an earlier rev by ad)
posted on tech-kern with no objections.

Remove the "struct lwp *" argument from all VFS and VOP interfaces.
The general trend is to remove it from all kernel interfaces and
this is a start. In case the calling lwp is desired, curlwp should
be used.

quick consensus on tech-kern

branches: 1.29.4;
Avoid stack allocation of large dirent structures in foo_readdir().

branches: 1.28.2; 1.28.4; 1.28.6; 1.28.8;
* nuke the nameidata parameter from VFS_MOUNT(). Nobody on tech-kern
knew what it was supposed to be used for and wrstuden gave a go-ahead
* while rototilling, convert file systems which went easily to
use VFS_PROTOS() instead of manually prototyping the methods

Use eopnotsupp() instead of vfs_stdsuspendctl() and retire the latter.

branches: 1.26.2;
Make set_statvfs_info() take a parameter for the vfs name instead
of always retrieving it from mp->mnt_op->vfs_name

christos ok

Change the VFS_MOUNT() interface so that the 'data' buffer passed to the
fs code is a kernel buffer, pass though the length of the buffer as well.
Since the length of the userspace buffer isn'it (yet) passed through the mount
system call, add a field to the vfsops structure containing the default length.
Split sys_mount() for calls from compat code.
Ride one of the recent kernel version changes - old fs LKMs will load, but
sys_mount() will reject any attempt to use them.

Using POOL_INIT here makes no sense, since file systems always have
an init method. So get rid of it and #ifdef _LKM and just always
init in the init method. Give malloc types the same treatment.
Makes file systems nicer to work with in linksetless environments
and fixes a few LKM discrepancies.

branches: 1.23.6; 1.23.8;
New file system suspension API to replace vn_start_write and vn_finished_write.
The suspension helpers are now put into file system specific operations.
This means every file system not supporting these helpers cannot be suspended
and therefore snapshots are no longer possible.

Implemented for file systems of type ffs.

The new API is enabled on a kernel option NEWVNGATE. This option is
not enabled by default in any kernel config.

Presented and discussed on tech-kern with much input from
Bill Studenmund <wrstuden@netbsd.org> and YAMAMOTO Takashi <yamt@netbsd.org>.

Welcome to 4.99.9 (new vfs op vfs_suspendctl).

a smorgasbord of improvements to vnode locking and path lookup:
- LOCKPARENT is no longer relevant for lookup(), relookup() or VOP_LOOKUP().
these now always return the parent vnode locked. namei() works as before.
lookup() and various other paths no longer acquire vnode locks in the
wrong order via vrele(). fixes PR 32535.
as a nice side effect, path lookup is also up to 25% faster.
- the above allows us to get rid of PDIRUNLOCK.
- also get rid of WANTPARENT (just use LOCKPARENT and unlock it).
- remove an assumption in layer_node_find() that all file systems implement
a recursive VOP_LOCK() (unionfs doesn't).
- require that all file systems supply vfs_vptofh and vfs_fhtovp routines.
fill in eopnotsupp() for file systems that don't support being exported
and remove the checks for NULL. (layerfs calls these without checking.)
- in union_lookup1(), don't change refcounts in the ISDOTDOT case, just
adjust which vnode is locked. fixes PR 33374.
- apply fixes for ufs_rename() from ufs_vnops.c rev. 1.61 to ext2fs_rename().

branches: 1.21.2;
__unused removal on arguments; approved by core.

- sprinkle __unused on function decls.
- fix a couple of unused bugs
- no more -Wno-unused for i386

branches: 1.19.2; 1.19.4;
add missing initializers

Use the LWP cached credentials where sane.

Make this compile again.

Don't allocate too much stuff on the stack.

branches: 1.15.4;
integrate kauth.

Do the count check after we process getargs.

Strip the chrooted portion of the path from the reported pty path. Reported
and tested by Lasse Kliemann. Thanks!

branches: 1.12.4; 1.12.6; 1.12.8; 1.12.10; 1.12.12;
merge ktrace-lwp.

use a counter to prevent from mounting ptyfs twice. Using save_ptm is not
good enough, because if we don't have COMPAT_BSDPTY, then it will stay NULL.

Move the duplicate mount check sooner, and fix a leak.

Apply the NFS exports list rototill patch:

- Remove all NFS related stuff from file system specific code.
- Drop the vfs_checkexp hook and generalize it in the new nfs_check_export
function, thus removing redundancy from all file systems.
- Move all NFS export-related stuff from kern/vfs_subr.c to the new
file sys/nfs/nfs_export.c. The former was becoming large and its code
is always compiled, regardless of the build options. Using the latter,
the code is only compiled in when NFSSERVER is enabled. While doing this,
also make some functions in nfs_subs.c conditional to NFSSERVER.
- Add a new command in nfssvc(2), called NFSSVC_SETEXPORTSLIST, that takes a
path and a set of export entries. At the moment it can only clear the
exports list or append entries, one by one, but it is done in a way that
allows setting the whole set of entries atomically in the future (see the
comment in mountd_set_exports_list or in doc/TODO).
- Change mountd(8) to use the nfssvc(2) system call instead of mount(2) so
that it becomes file system agnostic. In fact, all this whole thing was
done to remove a 'XXX' block from this utility!
- Change the mount*, newfs and fsck* userland utilities to not deal with NFS
exports initialization; done internally by the kernel when initializing
the NFS support for each file system.
- Implement an interface for VFS (called VFS hooks) so that several kernel
subsystems can run arbitrary code upon receipt of specific VFS events.
At the moment, this only provides support for unmount and is used to
destroy NFS exports lists from the file systems being unmounted, though it
has room for extension.

Thanks go to yamt@, chs@, thorpej@, wrstuden@ and others for their comments
and advice in the development of this patch.

branches: 1.8.2;
- rename variables to avoid shadowing.
- add a few const.

Remove compat code that hard-codes default group and mode for pty creation.
Hi Matt!

- Define a VFS_ATTACH() macro that places a reference to a vfsops structure
into the "vfsops" link set.
- Use VFS_ATTACH() where vfsops are declared for individual file systems.
- In vfsinit(), traverse the "vfsops" link set, rather than vfs_list_initial[].

nuke trailing whitespace

branches: 1.4.2; 1.4.4;
make this compile again; hi potr

Add pty group and mode settings.

branches: 1.2.2;
update #include path to fs/ptyfs/

move ptyfs off sys/miscfs/ptyfs/ to sys/fs/ptyfs/