branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8; 1.1.20;
Install mount argument structure header just like every other file system.

Make VOP_LINK return directory still locked and referenced.

Ride 7.99.10 bump.

branches: 1.7.18; 1.7.36;
Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.6.52; 1.6.74; 1.6.76;
Audit kqueue notifications. The reference behavior is taken from MFS and
is represented in the regression tests.

Exporting tmpfs file systems through NFS now works. Sure, file handles are
not persistent across reboots but neither are those of MFS, which we are
trying to replace. We should probably warn the user somehow, but not
prevent him doing this if he really wants to.

While here add a "reply" to the code-style change item.

add one code style and one knote-related item

branches: 1.3.6; 1.3.26; 1.3.30; 1.3.32;
Synchronize NFS status with reality. After yamt@ changes (I think with the
implementation of getpages and putpages and the use of UBC in the read and
write operations), the worst problem has gone away which was a panic when
a file's contents were modified in the original file system and then read
through the NFS mount point.

Also remove the entry about optimization. While tmpfs still has room for
improvement, it has become a lot better lately, thanks to the string pools
and the changes yamt@ did in the anonymous objects handling.

Fix typo, add missing parenthesis.

Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

Define filesystem attributes with vfs dependency.

branches: 1.5.2;
Adapt tmpfs_rename to use genfs_rename.

branches: 1.4.8; 1.4.12;
Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.3.2;
Don't generate unused fs_thefs.h headers.

branches: 1.2.18; 1.2.76; 1.2.98;
merge ktrace-lwp.

branches: 1.1.6;
Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

PR kern/55268: tmpfs is slow

tmpfs_getpages(): handle the PGO_LOCKED case and implement lazy update of
atime/mtime.

s/static inline/static __inline/g for consistency.

branches: 1.54.12;
Change the protocol to update a mounted file system from read-write
to read-only and vice versa:

- Add an internal flag IMNT_WANTRDONLY.
- Set either IMNT_WANTRDWR or IMNT_WANTRDONLY if going from or to read-only.
- After successfull call to VFS_MOUNT() set or clear MNT_RDONLY.

Adapt tmpfs and rumpfs to the new protocol. Other file systems will be
updated when they get the IMNT_CAN_RWTORO property.

Welcome to 7.99.64

Run vflush() when going from read/write to read only.

branches: 1.52.2; 1.52.4;
Change tmpfs to vcache.
- Use tmpfs node address as key.
- Remove tn_vlock, field tn_vnode now protected by vcache.
- Add a hold count to tmpfs node to prevent nodes from disappearing
while tmpfs_fhtovp() trys to vcache_get() them. Last holder
destroys reclaimed nodes.
- Remove the now unneeded parent unlock/lock for lookup of '..'.

Use VFS_PROTOS() for tmpfs.

branches: 1.50.4;
Remove the hardcoded 4 MB free kernel memory limit and replace it
by uvmexp.freetarg, as discussed on tech-kern.
Main purpose is to make tmpfs usable (as far as possible) on small memory
machines.
This is a bit experimental, but we need to give it some real world exposure
to see how well it works.

handle MNT_UPDATE

branches: 1.48.2;
- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

Make tmpfs_node_t::tn_gen a 32-bit number, keep it in sync with tmpfs_fid_t.
Also, change tn_status to unsigned while here.

tmpfs: replace the broken tmpfs_dircookie() logic which uses the node
address truncated to 31 bits (required for 32-bit readdir compatibility,
e.g. linux32). Instead, assign 2^31 range using the following logic:
- The first half of the 2^31 is assigned incrementally (the fast path).
- When exceeded, use the second half of 2^31, but manage with vmem(9).

It will require 2 billion files per-directory to trigger vmem(9) usage.
Also, while here, add some fixes for tmpfs_unmount().

Should fix PR/47739, PR/47480, PR/46088 and PR/41068.
Thanks to wiz@ for stress testing.

branches: 1.45.2; 1.45.12; 1.45.16;
define and use TMPFS_MAXNAMLEN instead of MAXNAMLEN

- Rework and document inode reference counting. Also document inode life
cycle (destruction part). Perform link counting in tmpfs_dir_attach()
and tmpfs_dir_detach(), instead of alloc/free and arbitrary places.
Fixes PR/44285, PR/44288, PR/44657 and likely PR/42484.

- Fix the race between the lookup and inode destruction. Fixes PR/43167
and its duplicates PR/40088, PR/40757.

- Improve tmpfs_rename() locking a little, fix kqueue event notifications
and also fix PR/43617. Add simplistic tmpfs_parentcheck_p(); to be
expanded and used for further rename() locking fixes.

- Cache directory entry "hint" in the tmpfs node, add tmpfs_dir_cached(),
and thus avoid unnecessary lookup in tmpfs_remove() and tmpfs_rmdir().

- Set correct _PC_FILESIZEBITS value in tmpfs_pathconf(). Fixes PR/43576.

- Few minor fixes.

undo the multiple inclusion protection part.

- Prevent tmpfs.h from inclusion in userland.
- Clean up and KNF tmpfs.h a little bit.

- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

- tmpfs: do not create dirent/node pools per-mount, there is no need to.
- tmpfs_mount: fix a leak of mount structures in error path.

branches: 1.39.2;
Add some support for unionfs (not built by default). It's still
missing at least opaque directory support, but until someone figures
out how that should work on ffs (see PR kern/kern/44383), there's
no point in trying to figure out how it should work here.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.37.14; 1.37.16;
Solve the fstat-wants-to-look-at-kernel-data-structures in a nicer
way: don't export the fs internals to innocent userspace programs
which just want to mount the file system.

shuffle around some more defs for fstat

noticed by Kurt Schreiner on current-users

Install mount argument structure header just like every other file system.

branches: 1.34.2;
- setting the birthdate is valid in setattr.
- don't call nanotime if not needed.
- don't call tempfs_update() if tempfs_chtimes succeeded, because it just did.

branches: 1.33.2; 1.33.4;
Remove clause 3 and 4 from TNF licenses

branches: 1.32.6; 1.32.8; 1.32.10;
u_int is not a C99 standard type, so spell it out completely as
unsigned int.

Drop trailing whitespace.

Merge vmlocking2 to head.

branches: 1.29.4;
Remove cn_lwp from struct componentname. curlwp should be used
from on. The NDINIT() macro no longer takes the lwp parameter and
associates the credentials of the calling thread with the namei
structure.

branches: 1.28.2;
Back out the tmpfs changes; there appears to be a bug lurking.

Merge from vmlocking.

branches: 1.26.4; 1.26.16; 1.26.18; 1.26.24;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.24.4;
Fix typo in comment.

Protect the dircookie stuff with _KERNEL. Fixes build problems of
mount_tmpfs as reported by Hisashi T Fujinaka in private mail.

Truncate directory cookies to 31 bits to avoid problems exposed in Linux
binaries which cast the returned values to 64-bits and fail due to sign
expansion. More details are provided in the big comment in tmpfs.h that
describes how the new tmpfs_dircookie works.

This is a rather ugly hack that shall be fixed with a cleaner solution,
but this resolves the problem in an effective way.

Fixes kern PR/32034.

branches: 1.21.4; 1.21.6;
Use the LWP cached credentials where sane.

branches: 1.20.4;
hide more by ifdef _KERNEL.

branches: 1.19.2;
integrate kauth.

Swap the order of the tf_gen and tf_id members of struct tmpfs_fid,
since tf_id needs 8-byte alignment on some architectures (like amd64).
struct tmpfs_fid now fits in 16 bytes on amd64 again.
OK matt@

Restrict generation numbers to 32bit values - we would have had to bump
_VFS_MAXFIDSZ to 24 otherwise for 64bit archs.

branches: 1.16.2; 1.16.4; 1.16.6;
Change "inline" back to "__inline" in .h files -- C99 is still too
new, and some apps compile things in C89 mode. C89 keywords stay.

As per core@.

Do not use unnamed structures/unions without instances; they break the
build under vax because of gcc 2.95. Found by he@.

make the include files usable from userland.

branches: 1.13.2; 1.13.4; 1.13.6;
Remove a conditional by always using inlined functions in favour of macros.
This way, the code is clearer and there shouldn't be any performance
difference (if the compiler DTRT). Suggested by chs@.

merge ktrace-lwp.

VFS_TO_TMPFS: remove a wrong assertion.
it's wrong because TMPFS_PAGES_MAX can be decreased.

- protect userland exported files against multiple inclusion.
- make sure that kernel only files don't compile in userland using #error
- XXX: some kernel only files still get installed.
- XXX: some files used in userland, don't get installed.

branches: 1.9.2;
merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.8.2;
Implement the tmpfs_advlock operation. Makes "user-level" file locking
work (aka lockf(3)).

tmpfs_getattr: return up-to-date timestamps.

Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

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.

change the way to handle directory "offsets" so that
they won't be changed when removing entries in the directory.
some applications like cvs rely on this.

- don't waste/leak kva.
- implement getpages/putpages. support mmap.
- eliminate meaningless memcpy.
- ubcify.

wiz@ remembers that the preferred way to spell file-system in NetBSD is
file system.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

branches: 1.3.2; 1.3.4; 1.3.6; 1.3.18;
Solve the fstat-wants-to-look-at-kernel-data-structures in a nicer
way: don't export the fs internals to innocent userspace programs
which just want to mount the file system.

shuffle around some more defs for fstat

noticed by Kurt Schreiner on current-users

branches: 1.1.2;
Install mount argument structure header just like every other file system.

Abolish all the silly indirection macros for initializing vnode ops tables.

These are things of the form #define foofs_op genfs_op, or #define
foofs_op genfs_eopnotsupp, or similar. They serve no purpose besides
obfuscation, and have gotten cutpasted all over everywhere.

Part 2; cvs randomly didn't commit these changes before, and then hid
them from me until I touched the files to force it to rethink. Dunno
what happened.

There's probably more of these, going to have to scan the tree the
hard way.

Use macros for the canned parts of device and fifo vnode op tables.

Add GENFS_SPECOP_ENTRIES and GENFS_FIFOOP_ENTRIES macros that contain
the portion of the vnode ops table declaration that is
(conservatively) the same in every fs. Use these in every fs that
supports devices and/or fifos with separate ops tables.

Note that ptyfs works differently (it has one type of vnode with
open-coded dispatch to the specfs code, which I haven't changed in
this commit) and rump/librump/rumpvfs/rumpfs.c has an indirect dynamic
dispatch that already does more or less the same thing, which I also
haven't changed.

Also note that this anticipates a few bits in the next changeset here
and there, and adds missing but unreachable calls in some cases (e.g.
most fses weren't defining whiteout on devices and fifos, but it isn't
reachable there), and it changes parsepath on devices and fifos to
genfs_badop from genfs_parsepath (but it's not reachable there
either).

It appears that devices in kernfs were missing kqfilter, so it's
possible that if you try to use kqueue on /kern/rootdev that it'll
explode.

And finally note that the ops declaration tables aren't
order-dependent. (Other than vop_default_desc has to come first.)
Otherwise this wouldn't work.

- Add a new vnode op: VOP_PARSEPATH.
- Move namei_getcomponent to genfs_vnops.c and call it genfs_parsepath.
- Add a parsepath entry to every vnode ops table.

VOP_PARSEPATH takes a directory vnode to be searched and a complete
following path and chooses how much of that path to consume. To begin
with, all parsepath calls are genfs_parsepath, which locates the first
'/' as always.

Note that the call doesn't take the whole struct componentname, only
the string. The other bits of struct componentname should not be
needed and there's no reason to cause potential complications by
exposing them.

branches: 1.12.6;
Add ACL support for FFS. From FreeBSD.

Add VOP_FALLOCATE and VOP_FDISCARD to every vnode ops table I can
find.

The filesystem ones all call genfs_eopnotsupp - right now I am only
implementing the plumbing and we can implement fallocate and/or
fdiscard for files later.

The device ones call spec_fallocate (which is also genfs_eopnotsupp)
and spec_fdiscard, which dispatches to the device-level op.

The fifo ones all call vn_fifo_bypass, which also ends up being
EOPNOTSUPP.

branches: 1.10.2;
- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

branches: 1.9.4; 1.9.14; 1.9.18;
- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

branches: 1.8.18; 1.8.24;
add arg so it will compile.

branches: 1.7.2; 1.7.4;
Remove clause 3 and 4 from TNF licenses

branches: 1.6.6; 1.6.8; 1.6.10;
Remove VOP_LEASE. Discussed on tech-kern.

branches: 1.5.18; 1.5.48; 1.5.54;
merge ktrace-lwp.

branches: 1.4.2;
merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.3.2;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

wiz@ remembers that the preferred way to spell file-system in NetBSD is
file system.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

Abolish all the silly indirection macros for initializing vnode ops tables.

These are things of the form #define foofs_op genfs_op, or #define
foofs_op genfs_eopnotsupp, or similar. They serve no purpose besides
obfuscation, and have gotten cutpasted all over everywhere.

branches: 1.8.72;
- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

branches: 1.7.2;
Stop exposing fifofs internals and leave only fifo_vnodeop_p visible.

branches: 1.6.20; 1.6.22;
Remove clause 3 and 4 from TNF licenses

branches: 1.5.6; 1.5.8; 1.5.10;
Remove VOP_LEASE. Discussed on tech-kern.

branches: 1.4.18; 1.4.48; 1.4.54;
- protect userland exported files against multiple inclusion.
- make sure that kernel only files don't compile in userland using #error
- XXX: some kernel only files still get installed.
- XXX: some files used in userland, don't get installed.

branches: 1.3.2;
merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.2.2;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

tmpfs: Nix trailing whitespace. No functional change intended.

uvm_availmem(): give it a boolean argument to specify whether a recent
cached value will do, or if the very latest total must be fetched. It can
be called thousands of times a second and fetching the totals impacts not
only the calling LWP but other CPUs doing unrelated activity in the VM
system.

Rename uvm_free() -> uvm_availmem().

uvmexp.free -> uvm_free()

Remove the roundups, they are incorrect and cause memcmp to wrongfully fail
because of uninitialized bytes at the end of the buffers.

ok rmind@

branches: 1.9.8; 1.9.16;
Two fixes from rmind

- tmpfs_node_get: restore (decrement) the node count on the error path.
- tmpfs_bytes_max: save the value of uvmexp.freetarg (since it is
unlocked/racy).

branches: 1.8.4;
use psize_t for physical memory calculation

Make sure to expand "freepages" to 64bit before shifting to byte values -
on rump we may have all our virtual address space "free".
Pointed out by pooka@.

Remove the hardcoded 4 MB free kernel memory limit and replace it
by uvmexp.freetarg, as discussed on tech-kern.
Main purpose is to make tmpfs usable (as far as possible) on small memory
machines.
This is a bit experimental, but we need to give it some real world exposure
to see how well it works.

handle MNT_UPDATE

branches: 1.4.4; 1.4.14; 1.4.18; 1.4.28;
- tmpfs_alloc_node/tmpfs_free_node: move inode limiting into tmpfs_node_get()
and tmpfs_node_put(), update outdated/wrong comments and move/add asserts.
- tmpfs_mount: check for the version of arguments a bit earlier.

- tmpfs: do not create dirent/node pools per-mount, there is no need to.
- tmpfs_mount: fix a leak of mount structures in error path.

branches: 1.2.2; 1.2.4; 1.2.6; 1.2.8;
tmpfs_bytes_max: use MIN() rather than min(), which returns int.
Spotted by Wolfgang Solfrank.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.14.20; 1.14.22;
Remove clause 3 and 4 from TNF licenses

branches: 1.13.6; 1.13.8; 1.13.10;
u_int is not a C99 standard type, so spell it out completely as
unsigned int.

Merge vmlocking2 to head.

branches: 1.11.2; 1.11.6;
Don't KASSERT that the pool allocator returns a page - it might be
called with NOWAIT.

XXX: this is just a quick fix to stop the diagnostic panic. I
think ENOSPC should be treated elsewhere depending on how much
memory tmpfs claims.

Back out the tmpfs changes; there appears to be a bug lurking.

Merge from vmlocking.

branches: 1.8.2;
Put _tmpfs_ in the name of the pools instead of _pool_. Obviously
they're pools; it's not so obvious that they come from tmpfs. :-)

branches: 1.7.12; 1.7.14; 1.7.18;
Pass an ipl argument to pool_init/POOL_INIT to be used when initializing
the pool's lock.

branches: 1.6.2; 1.6.4; 1.6.8; 1.6.10;
Add 2006 to the copyright notice; should have done this when touching the
files before.

branches: 1.5.2; 1.5.4;
use c99 initializers

branches: 1.4.4; 1.4.8; 1.4.18;
merge ktrace-lwp.

branches: 1.3.6;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

- don't keep a reference to a variable on stack.
- remove a meaningless assumption about the order of structure members.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.7.20; 1.7.22;
Remove clause 3 and 4 from TNF licenses

branches: 1.6.48; 1.6.50; 1.6.52;
Add 2006 to the copyright notice; should have done this when touching the
files before.

branches: 1.5.12; 1.5.16; 1.5.18;
make the include files usable from userland.

branches: 1.4.2; 1.4.4; 1.4.6;
- protect userland exported files against multiple inclusion.
- make sure that kernel only files don't compile in userland using #error
- XXX: some kernel only files still get installed.
- XXX: some files used in userland, don't get installed.

branches: 1.3.6;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

- don't keep a reference to a variable on stack.
- remove a meaningless assumption about the order of structure members.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

Move a mis-placed KASSERT().

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.

Omit obsolete comment and needless __diagused marker.

Fix uninitialized variable: if 'tvp' is NULL, '*tdep' is not initialized.
This could have caused the KASSERT to wrongfully fire.

ok riastradh@

branches: 1.8.10; 1.8.18;
Fix typo in comment.

Change tmpfs to vcache.
- Use tmpfs node address as key.
- Remove tn_vlock, field tn_vnode now protected by vcache.
- Add a hold count to tmpfs node to prevent nodes from disappearing
while tmpfs_fhtovp() trys to vcache_get() them. Last holder
destroys reclaimed nodes.
- Remove the now unneeded parent unlock/lock for lookup of '..'.

branches: 1.6.6;
- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

tmpfs: replace the broken tmpfs_dircookie() logic which uses the node
address truncated to 31 bits (required for 32-bit readdir compatibility,
e.g. linux32). Instead, assign 2^31 range using the following logic:
- The first half of the 2^31 is assigned incrementally (the fast path).
- When exceeded, use the second half of 2^31, but manage with vmem(9).

It will require 2 billion files per-directory to trigger vmem(9) usage.
Also, while here, add some fixes for tmpfs_unmount().

Should fix PR/47739, PR/47480, PR/46088 and PR/41068.
Thanks to wiz@ for stress testing.

branches: 1.4.2;
Uncomment call to genfs_rename_cache_purge.

Fixes a side issue mentioned in PR kern/46990.

I left this commented to preserve the old behaviour of tmpfs_rename,
but it is obviously broken to omit the cache purge, and I'm surprised
nobody had encountered any problems with it until now.

Check tmpfs_rmdired_p after tmpfs_vnode_get when walking up the tree.

tmpfs_vnode_get drops all locks except possibly the reclaiming bit
lock to keep the tmpfs node from being reclaimed while we're still
interested in it. Consequently, it does not keep the directory's
existence invariant, so we must check that after tmpfs_vnode_get.

Fixes PR kern/46990. Tested by Wolfgang Stukenbrock.

branches: 1.2.2; 1.2.4; 1.2.6;
Fix omitted VN_KNOTE(fvp, NOTE_RENAME) in tmpfs_rename.

Missed that line while refactoring tmpfs_rename to use genfs_rename.

Adapt tmpfs_rename to use genfs_rename.

Abolish all the silly indirection macros for initializing vnode ops tables.

These are things of the form #define foofs_op genfs_op, or #define
foofs_op genfs_eopnotsupp, or similar. They serve no purpose besides
obfuscation, and have gotten cutpasted all over everywhere.

Part 2; cvs randomly didn't commit these changes before, and then hid
them from me until I touched the files to force it to rethink. Dunno
what happened.

There's probably more of these, going to have to scan the tree the
hard way.

Use macros for the canned parts of device and fifo vnode op tables.

Add GENFS_SPECOP_ENTRIES and GENFS_FIFOOP_ENTRIES macros that contain
the portion of the vnode ops table declaration that is
(conservatively) the same in every fs. Use these in every fs that
supports devices and/or fifos with separate ops tables.

Note that ptyfs works differently (it has one type of vnode with
open-coded dispatch to the specfs code, which I haven't changed in
this commit) and rump/librump/rumpvfs/rumpfs.c has an indirect dynamic
dispatch that already does more or less the same thing, which I also
haven't changed.

Also note that this anticipates a few bits in the next changeset here
and there, and adds missing but unreachable calls in some cases (e.g.
most fses weren't defining whiteout on devices and fifos, but it isn't
reachable there), and it changes parsepath on devices and fifos to
genfs_badop from genfs_parsepath (but it's not reachable there
either).

It appears that devices in kernfs were missing kqfilter, so it's
possible that if you try to use kqueue on /kern/rootdev that it'll
explode.

And finally note that the ops declaration tables aren't
order-dependent. (Other than vop_default_desc has to come first.)
Otherwise this wouldn't work.

- Add a new vnode op: VOP_PARSEPATH.
- Move namei_getcomponent to genfs_vnops.c and call it genfs_parsepath.
- Add a parsepath entry to every vnode ops table.

VOP_PARSEPATH takes a directory vnode to be searched and a complete
following path and chooses how much of that path to consume. To begin
with, all parsepath calls are genfs_parsepath, which locates the first
'/' as always.

Note that the call doesn't take the whole struct componentname, only
the string. The other bits of struct componentname should not be
needed and there's no reason to cause potential complications by
exposing them.

branches: 1.13.6;
Add ACL support for FFS. From FreeBSD.

Add VOP_FALLOCATE and VOP_FDISCARD to every vnode ops table I can
find.

The filesystem ones all call genfs_eopnotsupp - right now I am only
implementing the plumbing and we can implement fallocate and/or
fdiscard for files later.

The device ones call spec_fallocate (which is also genfs_eopnotsupp)
and spec_fdiscard, which dispatches to the device-level op.

The fifo ones all call vn_fifo_bypass, which also ends up being
EOPNOTSUPP.

branches: 1.11.2;
- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

branches: 1.10.4; 1.10.14; 1.10.18;
- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

branches: 1.9.18; 1.9.24;
add NULL arg so it will compile.

branches: 1.8.2; 1.8.4;
Remove clause 3 and 4 from TNF licenses

branches: 1.7.6; 1.7.8; 1.7.10;
Remove VOP_LEASE. Discussed on tech-kern.

branches: 1.6.18; 1.6.48; 1.6.54;
merge ktrace-lwp.

branches: 1.5.2;
merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

Bug fix: correct the sense of an if-condition in tmpfs_spec_close:
because VOP_UPDATE() usually succeeded, spec_close() was not usually
called. Only skip the spec_close() step if VOP_UPDATE() returns
an error result. Now /dev/watchdog works as expected when /dev/
is a tmpfs; previously, it was impossible to disarm a user-tickled
watchdog.

branches: 1.3.2;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

wiz@ remembers that the preferred way to spell file-system in NetBSD is
file system.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

Abolish all the silly indirection macros for initializing vnode ops tables.

These are things of the form #define foofs_op genfs_op, or #define
foofs_op genfs_eopnotsupp, or similar. They serve no purpose besides
obfuscation, and have gotten cutpasted all over everywhere.

branches: 1.8.72;
- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

branches: 1.7.22; 1.7.28;
Remove clause 3 and 4 from TNF licenses

branches: 1.6.6; 1.6.8; 1.6.10;
Remove VOP_LEASE. Discussed on tech-kern.

branches: 1.5.18; 1.5.48; 1.5.54;
- protect userland exported files against multiple inclusion.
- make sure that kernel only files don't compile in userland using #error
- XXX: some kernel only files still get installed.
- XXX: some files used in userland, don't get installed.

branches: 1.4.2;
merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

Bug fix: change tmpfs_spec_bwrite from tmpfs_bwrite to vn_bwrite,
per yamt's suggestion. Previously, if /dev/ was mounted on a tmpfs,
block device buffers were never flushed to disk. Trying to unmount
a dirty filesystem (umount /dev/wd0e, say) caused an endless stream
of vflushbuf warnings, because tmpfs_bwrite was not flushing buffers.
The fix told to me by yamt solves the problem.

branches: 1.2.2;
Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

tmpfs: Assert no arithmetic overflow in directory node tn_size.

Need >2^57 directory entries before this is a problem. If we created
a million per second, this would take over 4000 years.

tmpfs: Refuse sizes that overflow round_page.

Reported-by: syzbot+8dbeee84de15f86df65b@syzkaller.appspotmail.com
https://syzkaller.appspot.com/bug?id=4a27b9fe074f8d4b0afbe22969339b8dfdb157e8

tmpfs: Nix trailing whitespace. No functional change intended.

branches: 1.114.4;
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.

Round of uvm.h cleanup.

The poorly named uvm.h is generally supposed to be for uvm-internal
users only.

- Narrow it to files that actually need it -- mostly files that need
to query whether curlwp is the pagedaemon, which should maybe be
exposed by an external header.

- Use uvm_extern.h where feasible and uvm_*.h for things not exposed
by it. We should split up uvm_extern.h but this will serve for now
to reduce the uvm.h dependencies.

- Use uvm_stat.h and #ifdef UVMHIST uvm.h for files that use
UVMHIST(ubchist), since ubchist is declared in uvm.h but the
reference evaporates if UVMHIST is not defined, so we reduce header
file dependencies.

- Make uvm_device.h and uvm_swap.h independently includable while
here.

ok chs@

PR kern/55268: tmpfs is slow

tmpfs_getpages(): handle the PGO_LOCKED case and implement lazy update of
atime/mtime.

Add ACL support for FFS. From FreeBSD.

cache_enter_id(): give it a boolean parameter to indicate whether the cached
identity is valid.

PR kern/54759 (vm.ubc_direct deadlock when read()/write() into mapping of itself)

- Add new flag UBC_ISMAPPED which tells ubc_uiomove() the object is mmap()ed
somewhere. Use it to decide whether to do direct-mapped copy, rather than
poking around directly in the vnode in ubc_uiomove(), which is ugly and
doesn't work for tmpfs. It would be nicer to contain all this in UVM but
the filesystem provides the needed locking here (VV_MAPPED) and to
reinvent that would suck more.

- Rename UBC_UNMAP_FLAG() to UBC_VNODE_FLAGS(). Pass in UBC_ISMAPPED where
appropriate.

branches: 1.108.2;
Merge the remaining changes from the ad-namecache branch, affecting namei()
and getcwd():

- push vnode locking back as far as possible.
- do most lookups directly in the namecache, avoiding vnode locks & refs.
- don't block new refs to vnodes across VOP_INACTIVE().
- get shared locks for VOP_LOOKUP() if the file system supports it.
- correct lock types for VOP_ACCESS() / VOP_GETATTR() in a few places.

Possible future enhancements:

- make the lookups lockless.
- support dotdot lookups by being lockless and inferring absence of chroot.
- maybe make it work for layered file systems.
- avoid vnode references at the root & cwd.

tmpfs_reg_resize(): do nothing if newsize == oldsize.

UVM locking changes, proposed on tech-kern:

- Change the lock on uvm_object, vm_amap and vm_anon to be a RW lock.
- Break v_interlock and vmobjlock apart. v_interlock remains a mutex.
- Do partial PV list locking in the x86 pmap. Others to follow later.

branches: 1.105.2;
Add newly created vnodes to the namei cache. The rest of the filesystems
already did that (or they don't support writing). Discussed in tech-kern.

branches: 1.104.4;
Add "void *extra" argument to vcache_new() so a file system may
pass more information about the file to create.

Welcome to 8.99.30

branches: 1.103.2;
allow tmpfs files to be larger than 4GB.

branches: 1.102.8; 1.102.14;
Change tmpfs_chsize() to update mtime etc. even if "length == node->tn_size".

Adresses PR kern/51762 "mtime not updated by open(O_TRUNC)"

branches: 1.101.2;
Make sure that nde->td_node is NULL for asserts.
Thanks and from Mindaugas Rasiukevicius.

Fixes PR kern/50381.

This enum is likely to be made unsigned by the compiler, so the assertion
will not work and clang objects with -Wtautological-constant-out-of-range-compare

Change tmpfs to vcache.
- Use tmpfs node address as key.
- Remove tn_vlock, field tn_vnode now protected by vcache.
- Add a hold count to tmpfs node to prevent nodes from disappearing
while tmpfs_fhtovp() trys to vcache_get() them. Last holder
destroys reclaimed nodes.
- Remove the now unneeded parent unlock/lock for lookup of '..'.

Make vget always return vnode unlocked.

Convert callers who want locks to use vn_lock afterward.

Add extra argument so the compiler will report stragglers.

branches: 1.97.2;
Store symlinks without a NUL terminator so that lstat(2) returns the
correct length. Fixes the tmpfs part of PR kern/48864.

branches: 1.96.4;
Change vnode operations create, mknod, mkdir and symlink to return
the resulting vnode *vpp unlocked.

Discussed on tech-kern@

Welcome to 6.99.30

Change vnode operations create, mknod, mkdir and symlink to keep the
directory node dvp locked on return.

Discussed on tech-kern@

Welcome to 6.99.29

Allocate direntp on the stack in tmpfs_dir_getdents(), thus saving
calls to kmem_zalloc() and kmem_free(); OK rmind@. From OpenBSD.

Fix a race where thread1 runs VOP_REMOVE() and gets preempted in
tmpfs_reclaim() before the call to tmpfs_free_node(). Thread2
runs VFS_FHTOVP() and gets a new vnode attached to the node thread1
is about to destroy.

Change tmpfs_alloc_node() to always assign non-zero generation number
and tmpfs_inactive() to set the generation number of unlinked nodes
to zero.

- tmpfs_construct_node: prevent from the new node construction if the
directory was removed. Fixes the crash reported by Nicolas Joly.
- tmpfs_reclaim: avoid race by checking tn_links with the vnode locked.

tmpfs_reg_resize: use size_t.

- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

tmpfs_dir_getdotents: fix the recent regression, set the correct
d_fileno value for dot-dot. Spotted by Pedro Martelletto, thanks!

Make tmpfs_node_t::tn_gen a 32-bit number, keep it in sync with tmpfs_fid_t.
Also, change tn_status to unsigned while here.

tmpfs_dir_getdents: avoid leaking kernel memory to the userspace.
From Pedro Martelletto.

XXX: regress/sys/fs/getdents should be a part of the test suite

tmpfs_alloc_node: use cprng_fast64(), the old random(9) shall be removed.

Handle whiteout case in tmpfs_dir_detach() and tmpfs_unmount().

mark variable __diagused

tmpfs: replace the broken tmpfs_dircookie() logic which uses the node
address truncated to 31 bits (required for 32-bit readdir compatibility,
e.g. linux32). Instead, assign 2^31 range using the following logic:
- The first half of the 2^31 is assigned incrementally (the fast path).
- When exceeded, use the second half of 2^31, but manage with vmem(9).

It will require 2 billion files per-directory to trigger vmem(9) usage.
Also, while here, add some fixes for tmpfs_unmount().

Should fix PR/47739, PR/47480, PR/46088 and PR/41068.
Thanks to wiz@ for stress testing.

tmpfs: fix the zero-length symlink target case as NetBSD supports them.

tmpfs_alloc_node: it is less error-prone to store the link path with
the NIL terminator included. Adjust tmpfs_readlink() to exclude NIL.
Also, remove the check for zero-length and add some asserts.

- tmpfs_remove: check 'appendable' flag for the parent directory as well.
Patch from Pedro Martelletto.
- tmpfs_dir_detach: remove missleading check.
- tmpfs_link: remove unused variable.

branches: 1.79.2; 1.79.4;
Replace the remaining KAUTH_GENERIC_ISSUSER authorization calls with
something meaningful. All relevant documentation has been updated or
written.

Most of these changes were brought up in the following messages:

http://mail-index.netbsd.org/tech-kern/2012/01/18/msg012490.html
http://mail-index.netbsd.org/tech-kern/2012/01/19/msg012502.html
http://mail-index.netbsd.org/tech-kern/2012/02/17/msg012728.html

Thanks to christos, manu, njoly, and jmmv for input.

Huge thanks to pgoyette for spinning these changes through some build
cycles and ATF.

branches: 1.78.2;
First step of random number subsystem rework described in
<20111022023242.BA26F14A158@mail.netbsd.org>. This change includes
the following:

An initial cleanup and minor reorganization of the entropy pool
code in sys/dev/rnd.c and sys/dev/rndpool.c. Several bugs are
fixed. Some effort is made to accumulate entropy more quickly at
boot time.

A generic interface, "rndsink", is added, for stream generators to
request that they be re-keyed with good quality entropy from the pool
as soon as it is available.

The arc4random()/arc4randbytes() implementation in libkern is
adjusted to use the rndsink interface for rekeying, which helps
address the problem of low-quality keys at boot time.

An implementation of the FIPS 140-2 statistical tests for random
number generator quality is provided (libkern/rngtest.c). This
is based on Greg Rose's implementation from Qualcomm.

A new random stream generator, nist_ctr_drbg, is provided. It is
based on an implementation of the NIST SP800-90 CTR_DRBG by
Henric Jungheim. This generator users AES in a modified counter
mode to generate a backtracking-resistant random stream.

An abstraction layer, "cprng", is provided for in-kernel consumers
of randomness. The arc4random/arc4randbytes API is deprecated for
in-kernel use. It is replaced by "cprng_strong". The current
cprng_fast implementation wraps the existing arc4random
implementation. The current cprng_strong implementation wraps the
new CTR_DRBG implementation. Both interfaces are rekeyed from
the entropy pool automatically at intervals justifiable from best
current cryptographic practice.

In some quick tests, cprng_fast() is about the same speed as
the old arc4randbytes(), and cprng_strong() is about 20% faster
than rnd_extract_data(). Performance is expected to improve.

The AES code in src/crypto/rijndael is no longer an optional
kernel component, as it is required by cprng_strong, which is
not an optional kernel component.

The entropy pool output is subjected to the rngtest tests at
startup time; if it fails, the system will reboot. There is
approximately a 3/10000 chance of a false positive from these
tests. Entropy pool _input_ from hardware random numbers is
subjected to the rngtest tests at attach time, as well as the
FIPS continuous-output test, to detect bad or stuck hardware
RNGs; if any are detected, they are detached, but the system
continues to run.

A problem with rndctl(8) is fixed -- datastructures with
pointers in arrays are no longer passed to userspace (this
was not a security problem, but rather a major issue for
compat32). A new kernel will require a new rndctl.

The sysctl kern.arandom() and kern.urandom() nodes are hooked
up to the new generators, but the /dev/*random pseudodevices
are not, yet.

Manual pages for the new kernel interfaces are forthcoming.

branches: 1.77.2;
Finish and enable whiteout support for tmpfs:

- Enable VOP tmpfs_whiteout().
- Support ISWHITEOUT in tmpfs_alloc_file().
- Support DOWHITEOUT in tmpfs_remove() and tmpfs_rmdir().
- Make rmdir on a directory containing whiteouts working.

Should fix PR #35112 (tmpfs doesn't play well with unionfs).

Backout previous. May be I need more coffee.

- Use << PAGE_SHIFT rather than calling round_page again.
- No need to call uao_dropswap_range() here since uao_dropswap()
is already called for each pages by uvm_vnp_setsize().

Rename uvm_vnp_zerorange(struct vnode *, off_t, size_t) to
ubc_zerorange(struct uvm_object *, off_t, size_t, int) changing
the first argument to an uvm_object and adding a flags argument.

Modify tmpfs_reg_resize() to zero the backing store (aobj) instead
of the vnode. Ubc_purge() no longer panics when unmounting tmpfs.

Keep uvm_vnp_zerorange() until the next kernel version bump.

Welcome to 5.99.53! Merge rmind-uvmplock branch:

- Reorganize locking in UVM and provide extra serialisation for pmap(9).
New lock order: [vmpage-owner-lock] -> pmap-lock.

- Simplify locking in some pmap(9) modules by removing P->V locking.

- Use lock object on vmobjlock (and thus vnode_t::v_interlock) to share
the locks amongst UVM objects where necessary (tmpfs, layerfs, unionfs).

- Rewrite and optimise x86 TLB shootdown code, make it simpler and cleaner.
Add TLBSTATS option for x86 to collect statistics about TLB shootdowns.

- Unify /dev/mem et al in MI code and provide required locking (removes
kernel-lock on some ports). Also, avoid cache-aliasing issues.

Thanks to Andrew Doran and Joerg Sonnenberger, as their initial patches
formed the core changes of this branch.

branches: 1.72.2;
Fix non-DEBUG build.

- Rework and document inode reference counting. Also document inode life
cycle (destruction part). Perform link counting in tmpfs_dir_attach()
and tmpfs_dir_detach(), instead of alloc/free and arbitrary places.
Fixes PR/44285, PR/44288, PR/44657 and likely PR/42484.

- Fix the race between the lookup and inode destruction. Fixes PR/43167
and its duplicates PR/40088, PR/40757.

- Improve tmpfs_rename() locking a little, fix kqueue event notifications
and also fix PR/43617. Add simplistic tmpfs_parentcheck_p(); to be
expanded and used for further rename() locking fixes.

- Cache directory entry "hint" in the tmpfs node, add tmpfs_dir_cached(),
and thus avoid unnecessary lookup in tmpfs_remove() and tmpfs_rmdir().

- Set correct _PC_FILESIZEBITS value in tmpfs_pathconf(). Fixes PR/43576.

- Few minor fixes.

tmpfs_update: comment out assert for now.

tmpfs_dir_lookup: use 'name' variable in memcmp() as intended; fix warning.

- tmpfs_lookup: cache (cnp->cn_flags & ISLASTCN) in const bool; de-indent.
- Group tmpfs_{alloc,free}_dirent() with other dirent routines.

No functional changes.

- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

tmpfs_free_node: comment out assert, which can fire e.g. on shutdown.

- tmpfs_alloc_node/tmpfs_free_node: move inode limiting into tmpfs_node_get()
and tmpfs_node_put(), update outdated/wrong comments and move/add asserts.
- tmpfs_mount: check for the version of arguments a bit earlier.

tmpfs_alloc_vp:
- Do not check for vn_lock(9) error, if LK_RETRY.
- Fix/improve comments.

Make zero length symlinks work on tmpfs.

Fixes PR #43843 (tmpfs dies with kassert panic for 0 length symlink target)

branches: 1.62.2;
Add some support for unionfs (not built by default). It's still
missing at least opaque directory support, but until someone figures
out how that should work on ffs (see PR kern/kern/44383), there's
no point in trying to figure out how it should work here.

Abolish the SAVENAME and HASBUF flags. There is now always a buffer,
so the path in a struct componentname is now always valid during VOP
calls.

Abolish struct componentname's cn_pnbuf. Use the path buffer in the
pathbuf object passed to namei as work space instead. (For now a pnbuf
pointer appears in struct nameidata, to support certain unclean things
that haven't been fixed yet, but it will be going away in the future.)

This removes the need for the SAVENAME and HASBUF namei flags.

Make holding v_interlock mandatory for callers of vget().

Announced some time ago on tech-kern.

tmpfs_lookup: add comment, de-ident main path. No functional change.
tmpfs_dir_attach: add assert.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.56.2; 1.56.4;
Simplify tmpfs_itimes() and use vfs_timestamp(). Also, replace unnecessary
kmem_zalloc()s with kmem_alloc()s.

"kauth_action_t = KAUTH_VNODE_WRITE_FLAGS;" must be C**. However,
we still use plain ISO C, so additionally supply the variable name.
Compile-tested only, but at least that's some testing.

Implement the vnode scope and adapt tmpfs to use it.

Mailing list reference:

http://mail-index.netbsd.org/tech-kern/2009/07/04/msg005404.html

Extract the open-coded authorization logic for chtimes() from various
file-systems and put it in a single function, genfs_can_chtimes().

This also makes UDF follow the same policy as all other file-systems.

Mailing list reference:

http://mail-index.netbsd.org/tech-kern/2009/04/27/msg004951.html

Per discussion on tech-kern@:

- Replace use of label/goto with returns

- Rename, change prototype of, and move functions from vfs_subr.c to
genfs_vnops.c

Refactor some duplicated file-system code.

Proposed and received no objections on tech-kern@:

http://mail-index.netbsd.org/tech-kern/2009/04/18/msg004843.html

For chown make auth checks consistent with UFS. Fixes PR kern/40933.

- tmpfs_dir_lookup: simplify.
- add some assertions.

branches: 1.48.4; 1.48.6; 1.48.10;
- setting the birthdate is valid in setattr.
- don't call nanotime if not needed.
- don't call tempfs_update() if tempfs_chtimes succeeded, because it just did.

branches: 1.47.2; 1.47.4;
Remove clause 3 and 4 from TNF licenses

branches: 1.46.6; 1.46.8; 1.46.10;
u_int is not a C99 standard type, so spell it out completely as
unsigned int.

Drop trailing whitespace.

specfs changes for PR kern/37717 (raidclose() is no longer called on
shutdown). There are still problems with device access and a PR will be
filed.

- Kill checkalias(). Allow multiple vnodes to reference a single device.

- Don't play dangerous tricks with block vnodes to ensure that only one
vnode can describe a block device. Instead, prohibit concurrent opens of
block devices. As a bonus remove the unreliable code that prevents
multiple file system mounts on the same device. It's no longer needed.

- Track opens by vnode and by device. Issue cdev_close() when the last open
goes away, instead of abusing vnode::v_usecount to tell if the device is
open.

Merge vmlocking2 to head.

branches: 1.42.4;
Remove cn_lwp from struct componentname. curlwp should be used
from on. The NDINIT() macro no longer takes the lwp parameter and
associates the credentials of the calling thread with the namei
structure.

branches: 1.41.2;
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

Back out the tmpfs changes; there appears to be a bug lurking.

Merge from vmlocking.

branches: 1.38.4;
Merge from vmlocking:

- Split vnode::v_flag into three fields, depending on field locking.
- simple_lock -> kmutex in a few places.
- Fix some simple locking problems.

Avoid stack allocation of large dirent structures in foo_readdir().

branches: 1.36.2; 1.36.4; 1.36.6;
When resizing a node, first drop extra pages and zero tail, and only
then set the new size. Otherwise zerolen will always be, well, 0.

branches: 1.35.2; 1.35.6;
Merge some of the less invasive changes from the vmlocking branch:

- kthread, callout, devsw API changes
- select()/poll() improvements
- miscellaneous MT safety improvements

branches: 1.34.4; 1.34.6;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.32.2;
Consistent usage of KAUTH_GENERIC_ISSUSER.

Add KAUTH_SYSTEM_CHSYSFLAGS so we can get rid of the last three
securelevel references (ufs, ext2fs, tmpfs).

Intentionally undocumented.

__unused removal on arguments; approved by core.

Audit kqueue notifications. The reference behavior is taken from MFS and
is represented in the regression tests.

Randomly initialize the node's generation to make file handles less
predictable. This solves a problem that may appear when serving a tmpfs
over NFS: if the server reboots, newly allocated files should have
different file handles; otherwise the remote clients could access files
they were not supposed to touch.

Truncate directory cookies to 31 bits to avoid problems exposed in Linux
binaries which cast the returned values to 64-bits and fail due to sign
expansion. More details are provided in the big comment in tmpfs.h that
describes how the new tmpfs_dircookie works.

This is a rather ugly hack that shall be fixed with a cleaner solution,
but this resolves the problem in an effective way.

Fixes kern PR/32034.

Grr... cvs diff scrolled too much and I didn't notice there were some
unwanted changes in this file. Revert them; sorry.

When renaming a file, we have to modify the mtime of the directory holding
it, not the mtime of the file itself. This fixes the problems exposed when
unpacking software under a tmpfs and trying to build it because dependencies
were not calculated properly (e.g. autoconf 2.60 as reported by tls@).

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

branches: 1.23.2; 1.23.4;
comment out empty code

Use the LWP cached credentials where sane.

branches: 1.21.4;
merge FreeBSD timecounters from branch simonb-timecounters
- struct timeval time is gone
time.tv_sec -> time_second
- struct timeval mono_time is gone
mono_time.tv_sec -> time_uptime
- access to time via
{get,}{micro,nano,bin}time()
get* versions are fast but less precise
- support NTP nanokernel implementation (NTP API 4)
- further reading:
Timecounter Paper: http://phk.freebsd.dk/pubs/timecounter.pdf
NTP Nanokernel: http://www.eecis.udel.edu/~mills/ntp/html/kern.html

branches: 1.20.2;
kauth fallout

integrate kauth.

branches: 1.18.2; 1.18.4; 1.18.6;
Do not use unnamed structures/unions without instances; they break the
build under vax because of gcc 2.95. Found by he@.

branches: 1.17.2; 1.17.4; 1.17.6;
merge ktrace-lwp.

take into account memory used for file cache pages, and wired pages,
when calculating potential free space

simplify calculation of free swap space using uvm-exported statistics,
with thanks to yamt@ for useful hints.

branches: 1.14.2;
- ignore truncation for VCHR/VBLK/VFIFO as it used to be
before yamt-vop merge. PR/32049 from Atsushi Onoe.
- reject setattr which attempts to change size of VLNK/VSOCK.

branches: 1.13.2;
tmpfs_reg_resize: drop swap slots on truncation.
fix a problem pointed by jmmv@.

merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.11.2;
Explicitly initialize the tn_lockf field. I expect problems in some
situations otherwise...

tmpfs_getattr: return up-to-date timestamps.

Some style fixes in comments.

Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

fix buffer overrun for symbolic links. PR/31325.

tmpfs_dir_getdotdotdent: correct fileid.

change the way to handle directory "offsets" so that
they won't be changed when removing entries in the directory.
some applications like cvs rely on this.

- don't waste/leak kva.
- implement getpages/putpages. support mmap.
- eliminate meaningless memcpy.
- ubcify.

convert to use it nanotime, but don't call it unless it is necessary.

wiz@ remembers that the preferred way to spell file-system in NetBSD is
file system.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

Tmpfs_mount() uses tmpfs_unmount() for cleanup if set_statvfs_info() fails.
This will not work as tmpfs_unmount() needs a suspended file system.

Just call set_statvfs_info() before allocating the root vnode and add
and use a common error exit label.

Reported-by: syzbot+343f2bfea65a32ab4222@syzkaller.appspotmail.com

Merge the remaining changes from the ad-namecache branch, affecting namei()
and getcwd():

- push vnode locking back as far as possible.
- do most lookups directly in the namecache, avoiding vnode locks & refs.
- don't block new refs to vnodes across VOP_INACTIVE().
- get shared locks for VOP_LOOKUP() if the file system supports it.
- correct lock types for VOP_ACCESS() / VOP_GETATTR() in a few places.

Possible future enhancements:

- make the lookups lockless.
- support dotdot lookups by being lockless and inferring absence of chroot.
- maybe make it work for layered file systems.
- avoid vnode references at the root & cwd.

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: 1.75.2;
remove an always false check and its' "This can never happen?" comment.

branches: 1.74.4;
Add "void *extra" argument to vcache_new() so a file system may
pass more information about the file to create.

Welcome to 8.99.30

FIx performance regression from rmind@:

Just from a very quick look, it seems like a regression introduced with
the vcache changes: the MP-safe flag is set too late and not inherited
by the root vnode.

branches: 1.72.2; 1.72.8; 1.72.10;
remove checks for failure after memory allocation calls that cannot fail:

kmem_alloc() with KM_SLEEP
kmem_zalloc() with KM_SLEEP
percpu_alloc()
pserialize_create()
psref_class_create()

all of these paths include an assertion that the allocation has not failed,
so callers should not assert that again.

Change the protocol to update a mounted file system from read-write
to read-only and vice versa:

- Add an internal flag IMNT_WANTRDONLY.
- Set either IMNT_WANTRDWR or IMNT_WANTRDONLY if going from or to read-only.
- After successfull call to VFS_MOUNT() set or clear MNT_RDONLY.

Adapt tmpfs and rumpfs to the new protocol. Other file systems will be
updated when they get the IMNT_CAN_RWTORO property.

Welcome to 7.99.64

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

Run vflush() when going from read/write to read only.

branches: 1.68.2;
In the event that loading the root vnode fails, bail out of
tmpfs_mount instead of crashing.

Came up in PR 51436, where kmem issues caused internal allocations to
wrongly fail. However, that could happen for real sometime (e.g.
probably if you tried to mount a new tmpfs when the system was very
low on memory, or possibly for other reasons entirely) and crashing
isn't the ticket.

(This is not a fix for PR 51436)

branches: 1.67.2;
Implement most of mount -ur functionality for tmpfs. Remaining issue is
the question who is responsible for syncing pending writes, but the
functionality is good enough for serving as read-only chroot base in
bulk builds.

Only recheck size/node limits on update mounts, if there actually have
been specified.

Change tmpfs to vcache.
- Use tmpfs node address as key.
- Remove tn_vlock, field tn_vnode now protected by vcache.
- Add a hold count to tmpfs node to prevent nodes from disappearing
while tmpfs_fhtovp() trys to vcache_get() them. Last holder
destroys reclaimed nodes.
- Remove the now unneeded parent unlock/lock for lookup of '..'.

Use VFS_PROTOS() for tmpfs.

branches: 1.63.2; 1.63.4;
Check for invalid mount arguments early and gracefully fail the mount.
Spotted by pooka@

Remove the hardcoded 4 MB free kernel memory limit and replace it
by uvmexp.freetarg, as discussed on tech-kern.
Main purpose is to make tmpfs usable (as far as possible) on small memory
machines.
This is a bit experimental, but we need to give it some real world exposure
to see how well it works.

fix typo

handle MNT_UPDATE

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: 1.58.2;
Change all vfsops to use C99 designated initializers.

No functional changes intended.

Remove an annoying printf. And to answer the question: VFS_VGET() gets
used by NFS V3 server for readdirplus.

Fix a race where thread1 runs VOP_REMOVE() and gets preempted in
tmpfs_reclaim() before the call to tmpfs_free_node(). Thread2
runs VFS_FHTOVP() and gets a new vnode attached to the node thread1
is about to destroy.

Change tmpfs_fhtovp() to check the generation number after
tmpfs_vnode_get() succeeded.

- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

Handle whiteout case in tmpfs_dir_detach() and tmpfs_unmount().

tmpfs: replace the broken tmpfs_dircookie() logic which uses the node
address truncated to 31 bits (required for 32-bit readdir compatibility,
e.g. linux32). Instead, assign 2^31 range using the following logic:
- The first half of the 2^31 is assigned incrementally (the fast path).
- When exceeded, use the second half of 2^31, but manage with vmem(9).

It will require 2 billion files per-directory to trigger vmem(9) usage.
Also, while here, add some fixes for tmpfs_unmount().

Should fix PR/47739, PR/47480, PR/46088 and PR/41068.
Thanks to wiz@ for stress testing.

branches: 1.52.2; 1.52.8; 1.52.12; 1.52.14; 1.52.16; 1.52.22;
define and use TMPFS_MAXNAMLEN instead of MAXNAMLEN

- Rework and document inode reference counting. Also document inode life
cycle (destruction part). Perform link counting in tmpfs_dir_attach()
and tmpfs_dir_detach(), instead of alloc/free and arbitrary places.
Fixes PR/44285, PR/44288, PR/44657 and likely PR/42484.

- Fix the race between the lookup and inode destruction. Fixes PR/43167
and its duplicates PR/40088, PR/40757.

- Improve tmpfs_rename() locking a little, fix kqueue event notifications
and also fix PR/43617. Add simplistic tmpfs_parentcheck_p(); to be
expanded and used for further rename() locking fixes.

- Cache directory entry "hint" in the tmpfs node, add tmpfs_dir_cached(),
and thus avoid unnecessary lookup in tmpfs_remove() and tmpfs_rmdir().

- Set correct _PC_FILESIZEBITS value in tmpfs_pathconf(). Fixes PR/43576.

- Few minor fixes.

- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

- tmpfs_alloc_node/tmpfs_free_node: move inode limiting into tmpfs_node_get()
and tmpfs_node_put(), update outdated/wrong comments and move/add asserts.
- tmpfs_mount: check for the version of arguments a bit earlier.

- tmpfs: do not create dirent/node pools per-mount, there is no need to.
- tmpfs_mount: fix a leak of mount structures in error path.

Fix file handle operations for tmpfs by removing a now bogus test and
fixing the return value of tmpfs_fhtovp() in the not-found case.

When vmlocking2 was merged to head (Jan 2008 !!) the inode numbering was
changed. Before inodes were numbered 2..tm_nodes_max-1 and after the
merge the numbers are derived from the nodes memory address.

Fixes PR #43605 (tmpfs file handles are broken)

branches: 1.46.2;
tmpfs_statvfs: hold accounting lock, since tmpfs_pages_avail() and
tmpfs_bytes_max() may fluctuate while in calculations.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

branches: 1.44.4; 1.44.14; 1.44.16; 1.44.18; 1.44.22;
Solve the fstat-wants-to-look-at-kernel-data-structures in a nicer
way: don't export the fs internals to innocent userspace programs
which just want to mount the file system.

shuffle around some more defs for fstat

noticed by Kurt Schreiner on current-users

Install mount argument structure header just like every other file system.

branches: 1.41.2; 1.41.4;
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: 1.40.2;
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.

Remove clause 3 and 4 from TNF licenses

branches: 1.38.6; 1.38.8; 1.38.10;
Drop trailing whitespace.

Limit kva usage to 8TB and the number of inodes to 2G. Should fix
PR kern/37951.

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 bogus KASSERT: we can't make any assumptions about a dirent's
node in unmount since it might have been freed already.

fixes PR kern/37667. per discussion with ad & simonb.

Merge vmlocking2 to head.

branches: 1.33.4;
Remove cn_lwp from struct componentname. curlwp should be used
from on. The NDINIT() macro no longer takes the lwp parameter and
associates the credentials of the calling thread with the namei
structure.

branches: 1.32.2;
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

Back out the tmpfs changes; there appears to be a bug lurking.

Merge from vmlocking.

branches: 1.29.2;
Fix typo: I'm pretty sure that in tmpfs_done(), both of the malloc(9)
types are supposed to be detached, not attached.

branches: 1.28.2;
Avoid stack allocation of large dirent structures in foo_readdir().

branches: 1.27.2; 1.27.4; 1.27.6; 1.27.8;
Set mnt_fs_bshift and mnt_dev_bshift to reasonable dummy-values.

* 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: 1.24.2;
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.

Merge some of the less invasive changes from the vmlocking branch:

- kthread, callout, devsw API changes
- select()/poll() improvements
- miscellaneous MT safety improvements

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: 1.20.4; 1.20.6;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.18.2;
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).

__unused removal on arguments; approved by core.

Audit kqueue notifications. The reference behavior is taken from MFS and
is represented in the regression tests.

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

branches: 1.14.2; 1.14.4;
add missing initializers

Fix alignement problems for fhandle_t, exposed by gcc4.1.

While touching all vptofh/fhtovp functions, get rid of VFS_MAXFIDSIZ,
version the getfh(2) syscall and explicitly pass the size available in
the filehandle from userland.

Discussed on tech-kern, with lots of help from yamt (thanks!).

branches: 1.12.4; 1.12.6;
integrate kauth.

branches: 1.11.2; 1.11.4; 1.11.6;
Do not use unnamed structures/unions without instances; they break the
build under vax because of gcc 2.95. Found by he@.

branches: 1.10.2; 1.10.4; 1.10.6;
merge ktrace-lwp.

branches: 1.9.6;
Handle too big numbers given in the max size argument.

Only consider valid flags in the root mode's parameter given by the user.
I doubt the unchecked value could bring us problems, but better to be safe
than sorry.

Sanity check negative values in the maximum size and number of nodes
arguments to avoid a crash while mounting a tmpfs file system. Add a
regression test for this too. Noticed by chs@.

Kill the tmpfs(9) manual page; it was just documenting internal details of
tmpfs' "API" and was already rotting.

Instead, merge all the relevant comments into the code. This includes
acknowledgements to Google's Summer of Code 2005 program (they were in the
AUTHORS section of tmpfs(9) before), so all the files need to be changed
to include this sentence alongside the title. (Note that this was not a
requirement of the program.)

Start inode numbers on 2 to mimic UFS tradition (and to avoid problems if
some utility relies on this).

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.

Nodes cannot use the '0' identifier or they will be skipped by readdir.
E.g., the root node's '.' and '..' directory entries did not appear in
a directory list, because the root node always holds the first id.

wiz@ remembers that the preferred way to spell file-system in NetBSD is
file system.

Initial addition of tmpfs, an efficient memory file-system. This project
was developed as part of Google's Summer of Code 2005 program. This
change adds the kernel code, the mount_tmpfs utility, a regression test
suite and does all other related changes to integrate these.

The file-system is still *experimental*. Therefore, it is disabled by
default in all kernels. However, as typically done, a commented-out
entry is added in them to ease its setup.

Note that I haven't commited the required mountd(8) changes to be able
to export tmpfs file-systems because NFS support is still very unstable
and because, before enabling it, I'd like to do some other changes.

OK'ed by my project mentor, William Studenmund (wrstuden@).

tmpfs_read: respect MNT_NOATIME.

add a kauth vnode check for creating links

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.

Abolish all the silly indirection macros for initializing vnode ops tables.

These are things of the form #define foofs_op genfs_op, or #define
foofs_op genfs_eopnotsupp, or similar. They serve no purpose besides
obfuscation, and have gotten cutpasted all over everywhere.

- Add a new vnode op: VOP_PARSEPATH.
- Move namei_getcomponent to genfs_vnops.c and call it genfs_parsepath.
- Add a parsepath entry to every vnode ops table.

VOP_PARSEPATH takes a directory vnode to be searched and a complete
following path and chooses how much of that path to consume. To begin
with, all parsepath calls are genfs_parsepath, which locates the first
'/' as always.

Note that the call doesn't take the whole struct componentname, only
the string. The other bits of struct componentname should not be
needed and there's no reason to cause potential complications by
exposing them.

branches: 1.145.4;
Disable use of UBC_FAULTBUSY in tmpfs_write() for now,
which brings back zeroing of all new tmpfs data pages.
The existing code that enables this optimization skips the zeroing
in numerous cases where it is needed, resulting in corrupted files
and data leaks from the page's previous identity.

branches: 1.144.2;
Round of uvm.h cleanup.

The poorly named uvm.h is generally supposed to be for uvm-internal
users only.

- Narrow it to files that actually need it -- mostly files that need
to query whether curlwp is the pagedaemon, which should maybe be
exposed by an external header.

- Use uvm_extern.h where feasible and uvm_*.h for things not exposed
by it. We should split up uvm_extern.h but this will serve for now
to reduce the uvm.h dependencies.

- Use uvm_stat.h and #ifdef UVMHIST uvm.h for files that use
UVMHIST(ubchist), since ubchist is declared in uvm.h but the
reference evaporates if UVMHIST is not defined, so we reduce header
file dependencies.

- Make uvm_device.h and uvm_swap.h independently includable while
here.

ok chs@

Introduce genfs_pathconf() and use it for the default case in all filesystems.

tmpfs_write(): use UBC_FAULTBUSY when extending files, if possible, to avoid
zeroing of newly allocated pages & fault processing.

PR kern/32166: pgo_get protocol is ambiguous
Also problems with tmpfs+nfs noted by hannken@.

Don't pass PGO_ALLPAGES to pgo_get, and ignore PGO_DONTCARE in the
!PGO_LOCKED case. In uao_get() have uvm_pagealloc() take care of page
zeroing and release busy pages on error.

Minor correction to previous.

PR kern/55268: tmpfs is slow

tmpfs_getpages(): handle the PGO_LOCKED case and implement lazy update of
atime/mtime.

Add ACL support for FFS. From FreeBSD.

PR kern/55268: tmpfs is slow

Enter dotdot into the namecache.

PR kern/54759 (vm.ubc_direct deadlock when read()/write() into mapping of itself)

- Add new flag UBC_ISMAPPED which tells ubc_uiomove() the object is mmap()ed
somewhere. Use it to decide whether to do direct-mapped copy, rather than
poking around directly in the vnode in ubc_uiomove(), which is ugly and
doesn't work for tmpfs. It would be nicer to contain all this in UVM but
the filesystem provides the needed locking here (VV_MAPPED) and to
reinvent that would suck more.

- Rename UBC_UNMAP_FLAG() to UBC_VNODE_FLAGS(). Pass in UBC_ISMAPPED where
appropriate.

branches: 1.135.2;
tmpfs_inactive(): do like other file systems and truncate the file if it
has been deleted. Otherwise VFS will try to write cached data "back to
disc", which in the case of a UAO means needless page deactivations and
the resulting TLB shootdowns.

UVM locking changes, proposed on tech-kern:

- Change the lock on uvm_object, vm_amap and vm_anon to be a RW lock.
- Break v_interlock and vmobjlock apart. v_interlock remains a mutex.
- Do partial PV list locking in the x86 pmap. Others to follow later.

branches: 1.133.10; 1.133.16;
Make VOP_RECLAIM do the last unlock of the vnode.

VOP_RECLAIM naturally has exclusive access to the vnode, so having it
locked on entry is not strictly necessary -- but it means if there
are any final operations that must be done on the vnode, such as
ffs_update, requiring exclusive access to it, we can now kassert that
the vnode is locked in those operations.

We can't just have the caller release the last lock because some file
systems don't use genfs_lock, and require the vnode to remain valid
for VOP_UNLOCK to work, notably unionfs.

Change VOP_REMOVE and VOP_RMDIR to preserve lock/ref on dvp.

No change to vp -- the plan is to replace the node by the
componentname in the vop parameters, and let all directory vops do
lookups internally.

Proposed on tech-kern with no objections:
https://mail-index.netbsd.org/tech-kern/2017/04/17/msg021825.html

Make VOP_INACTIVE preserve vnode lock on return.

Discussed on tech-kern:
https://mail-index.netbsd.org/tech-kern/2017/04/01/msg021751.html

Ride 7.99.68, a bumpy bus of incremental vfs improvements!

Protect tmpfs_getpages() against reclaiming vnodes.

branches: 1.129.2;
Remove RO check in tmpfs_putpages for now, the syncer doesn't like the
error code.

Remove now obsolete operation vcache_remove().

Welcome to 7.99.36

branches: 1.127.2;
Backout previous - need coffee first

Mark a variable as __diagused.

do no access uninitialized variables in KASSERTs - fixes build

Implement most of mount -ur functionality for tmpfs. Remaining issue is
the question who is responsible for syncing pending writes, but the
functionality is good enough for serving as read-only chroot base in
bulk builds.

Change tmpfs to vcache.
- Use tmpfs node address as key.
- Remove tn_vlock, field tn_vnode now protected by vcache.
- Add a hold count to tmpfs node to prevent nodes from disappearing
while tmpfs_fhtovp() trys to vcache_get() them. Last holder
destroys reclaimed nodes.
- Remove the now unneeded parent unlock/lock for lookup of '..'.

Make VOP_LINK return directory still locked and referenced.

Ride 7.99.10 bump.

branches: 1.121.2;
Store symlinks without a NUL terminator so that lstat(2) returns the
correct length. Fixes the tmpfs part of PR kern/48864.

branches: 1.120.2;
Add VOP_FALLOCATE and VOP_FDISCARD to every vnode ops table I can
find.

The filesystem ones all call genfs_eopnotsupp - right now I am only
implementing the plumbing and we can implement fallocate and/or
fdiscard for files later.

The device ones call spec_fallocate (which is also genfs_eopnotsupp)
and spec_fdiscard, which dispatches to the device-level op.

The fifo ones all call vn_fifo_bypass, which also ends up being
EOPNOTSUPP.

tmpfs_mknod: it is not our responsibility to call vput() on the directory
vnode, so remove it (and ensure *vpp is NULL while here).

branches: 1.118.2;
The current implementation of vn_lock() is racy. Modification of
the vnode operations vector for active vnodes is unsafe because it
is not known whether deadfs or the original file system will be
called.

- Pass down LK_RETRY to the lock operation (hint for deadfs only).

- Change deadfs lock operation to return ENOENT if LK_RETRY is unset.

- Change all other lock operations to check for dead vnode once
the vnode is locked and unlock and return ENOENT in this case.

With these changes in place vnode lock operations will never succeed
after vclean() has marked the vnode as VI_XLOCK and before vclean()
has changed the operations vector.

Adresses PR kern/37706 (Forced unmount of file systems is unsafe)

Discussed on tech-kern.

Welcome to 6.99.33

Adapt my previous patch differently. read(2) wants EISDIR when the
object is a directory. Which also means that tmpfs_read() was returning
a wrong error code when dealing with non-regular vnodes.

Fix tmpfs_read()'s return value; it should return EINVAL. Now consistent with
tmpfs_write().

ok christos@

Change vnode operation lookup to return the resulting vnode *vpp unlocked.
Change cache_lookup() to return an unlocked vnode.

Discussed on tech-kern@

Welcome to 6.99.31

Change vnode operations create, mknod, mkdir and symlink to return
the resulting vnode *vpp unlocked.

Discussed on tech-kern@

Welcome to 6.99.30

Change vnode operations create, mknod, mkdir and symlink to keep the
directory node dvp locked on return.

Discussed on tech-kern@

Welcome to 6.99.29

Prevent a diagnostic assertion in tmpfs_rmdir() from being triggered
through an rmdir on ".." by moving it so it happens after the check for
empty directories; OK rmind@.

Fix a race where thread1 runs VOP_REMOVE() and gets preempted in
tmpfs_reclaim() before the call to tmpfs_free_node(). Thread2
runs VFS_FHTOVP() and gets a new vnode attached to the node thread1
is about to destroy.

Change tmpfs_alloc_node() to always assign non-zero generation number
and tmpfs_inactive() to set the generation number of unlinked nodes
to zero.

It is not the task of tmpfs_open() to check for unlinked nodes.

Fix tmpfs_lookup() to always return ENOENT when looking up from
an unlinked directory.

- tmpfs_construct_node: prevent from the new node construction if the
directory was removed. Fixes the crash reported by Nicolas Joly.
- tmpfs_reclaim: avoid race by checking tn_links with the vnode locked.

Fix previous, add __diagused.

- Simplify tmpfs_update(), eliminate tmpfs_note_t::tn_status and deferred
timestamp updates. Fix some incorrect updates and plug some missing ones.
Should fix PR/48385.
- tmpfs_rmdir: avoid O(n) scan when the directory is not empty and whiteout
entries were never added.

tmpfs: replace the broken tmpfs_dircookie() logic which uses the node
address truncated to 31 bits (required for 32-bit readdir compatibility,
e.g. linux32). Instead, assign 2^31 range using the following logic:
- The first half of the 2^31 is assigned incrementally (the fast path).
- When exceeded, use the second half of 2^31, but manage with vmem(9).

It will require 2 billion files per-directory to trigger vmem(9) usage.
Also, while here, add some fixes for tmpfs_unmount().

Should fix PR/47739, PR/47480, PR/46088 and PR/41068.
Thanks to wiz@ for stress testing.

tmpfs: fix the zero-length symlink target case as NetBSD supports them.

tmpfs_alloc_node: it is less error-prone to store the link path with
the NIL terminator included. Adjust tmpfs_readlink() to exclude NIL.
Also, remove the check for zero-length and add some asserts.

- tmpfs_remove: check 'appendable' flag for the parent directory as well.
Patch from Pedro Martelletto.
- tmpfs_dir_detach: remove missleading check.
- tmpfs_link: remove unused variable.

tmpfs_remove: as per POSIX, "if the file's link count is not 0, the last
file status change timestamp of the file shall be marked for update."

From Pedro Martelletto.

branches: 1.101.6;
C99 section 6.7.2.3 (Tags) Note 3 states that:

A type specifier of the form

enum identifier

without an enumerator list shall only appear after the type it
specifies is complete.

which means that we cannot pass an "enum vtype" argument to
kauth_access_action() without fully specifying the type first.
Unfortunately there is a complicated include file loop which
makes that difficult, so convert this minimal function into a
macro (and capitalize it).

(ok elad@)

Excise struct componentname from the namecache.

This uglifies the interface, because several operations need to be
passed the namei flags and cache_lookup also needs for the time being
to be passed cnp->cn_nameiop. Nonetheless, it's a net benefit.

The glop should be able to go away eventually but requires structural
cleanup elsewhere first.

This change requires a kernel bump.

Disentangle the namecache from the internals of namei.

- Move the namecache's hash computation to inside the namecache code,
instead of being spread out all over the place. Remove cn_hash from
struct componentname and delete all uses of it.

- It is no longer necessary (if it ever was) for cache_lookup and
cache_lookup_raw to clear MAKEENTRY from cnp->cn_flags for the cases
that cache_enter already checks for.

- Rearrange the interface of cache_lookup (and cache_lookup_raw) to
make it somewhat simpler, to exclude certain nonexistent error
conditions, and (most importantly) to make it not require write access
to cnp->cn_flags.

This change requires a kernel bump.

branches: 1.98.2;
Move some the test for MAKEENTRY into the cache_enter(9). Make some
variables in vfs_cache.c static, __read_mostly, etc.

No objection on tech-kern@.

Adapt tmpfs_rename to use genfs_rename.

Replace the remaining KAUTH_GENERIC_ISSUSER authorization calls with
something meaningful. All relevant documentation has been updated or
written.

Most of these changes were brought up in the following messages:

http://mail-index.netbsd.org/tech-kern/2012/01/18/msg012490.html
http://mail-index.netbsd.org/tech-kern/2012/01/19/msg012502.html
http://mail-index.netbsd.org/tech-kern/2012/02/17/msg012728.html

Thanks to christos, manu, njoly, and jmmv for input.

Huge thanks to pgoyette for spinning these changes through some build
cycles and ATF.

in tmpfs_readdir(), skip the . and .. processing on removed directories,
since the latter will crash in this case.

branches: 1.94.2;
tmpfs_access: simplify, no need to separate the logic.

branches: 1.93.4;
Obey MNT_RELATIME, the only addition is that mkdir in ufs sets IN_ACCESS too.

branches: 1.92.2;
return TMPFS_MAXNAMLEN instead of NAME_MAX

define and use TMPFS_MAXNAMLEN instead of MAXNAMLEN

Finish and enable whiteout support for tmpfs:

- Enable VOP tmpfs_whiteout().
- Support ISWHITEOUT in tmpfs_alloc_file().
- Support DOWHITEOUT in tmpfs_remove() and tmpfs_rmdir().
- Make rmdir on a directory containing whiteouts working.

Should fix PR #35112 (tmpfs doesn't play well with unionfs).

Fix tmpfs_rename locking.

Fixes PR kern/36681. tmpfs now survives dirconc, all our vfs/tmpfs
tests and rename races in atf, and a bunch of hand-written tests
that I'd commit if atf didn't find them highly indigestible.

ok dholland

Fix renaming over mismatched non-directory types in tmpfs.

Renaming a file of any non-directory type over another file of any
other non-directory type is OK -- they need not match as long as
neither is a directory, so loosen the kassert to reflect this.

XXX Need to write test cases for this.

ok dholland, rmind

Welcome to 5.99.53! Merge rmind-uvmplock branch:

- Reorganize locking in UVM and provide extra serialisation for pmap(9).
New lock order: [vmpage-owner-lock] -> pmap-lock.

- Simplify locking in some pmap(9) modules by removing P->V locking.

- Use lock object on vmobjlock (and thus vnode_t::v_interlock) to share
the locks amongst UVM objects where necessary (tmpfs, layerfs, unionfs).

- Rewrite and optimise x86 TLB shootdown code, make it simpler and cleaner.
Add TLBSTATS option for x86 to collect statistics about TLB shootdowns.

- Unify /dev/mem et al in MI code and provide required locking (removes
kernel-lock on some ports). Also, avoid cache-aliasing issues.

Thanks to Andrew Doran and Joerg Sonnenberger, as their initial patches
formed the core changes of this branch.

branches: 1.86.2;
- tmpfs_getattr: perform tmpfs_update() before fetching the timestamps.
- tmpfs_rmdir: detach after tn_links decrement, so that correct event
i.e. NOTE_DELETE would be trigerred.

- Rework and document inode reference counting. Also document inode life
cycle (destruction part). Perform link counting in tmpfs_dir_attach()
and tmpfs_dir_detach(), instead of alloc/free and arbitrary places.
Fixes PR/44285, PR/44288, PR/44657 and likely PR/42484.

- Fix the race between the lookup and inode destruction. Fixes PR/43167
and its duplicates PR/40088, PR/40757.

- Improve tmpfs_rename() locking a little, fix kqueue event notifications
and also fix PR/43617. Add simplistic tmpfs_parentcheck_p(); to be
expanded and used for further rename() locking fixes.

- Cache directory entry "hint" in the tmpfs node, add tmpfs_dir_cached(),
and thus avoid unnecessary lookup in tmpfs_remove() and tmpfs_rmdir().

- Set correct _PC_FILESIZEBITS value in tmpfs_pathconf(). Fixes PR/43576.

- Few minor fixes.

- tmpfs_lookup: cache (cnp->cn_flags & ISLASTCN) in const bool; de-indent.
- Group tmpfs_{alloc,free}_dirent() with other dirent routines.

No functional changes.

- Describe some locking.
- Add VOP argument comments, add some asserts.
- Update/fix/remove outdated/missleading comments.
- Clean up, de-indent, KNF, misc.

No functional changes intended.

Add comments, clean up.

Remove cache_purge(9) calls from reclamation routines in the file systems,
as vclean(9) performs it for us since Lite2 merge.

yes, more C99 please (back out previous change).

no c99 please.

Constify, update some comments, use memset() to clear pgs.

sys_link: prevent hard links on directories (cross-mount operations are
already prevented). File systems are no longer responsible to check this.
Clean up and add asserts (note that dvp == vp cannot happen in vop_link).

OK dholland@

branches: 1.76.2;
Add some support for unionfs (not built by default). It's still
missing at least opaque directory support, but until someone figures
out how that should work on ffs (see PR kern/kern/44383), there's
no point in trying to figure out how it should work here.

Abolish the SAVENAME and HASBUF flags. There is now always a buffer,
so the path in a struct componentname is now always valid during VOP
calls.

Abolish struct componentname's cn_pnbuf. Use the path buffer in the
pathbuf object passed to namei as work space instead. (For now a pnbuf
pointer appears in struct nameidata, to support certain unclean things
that haven't been fixed yet, but it will be going away in the future.)

This removes the need for the SAVENAME and HASBUF namei flags.

return same errno as ffs

tmpfs_lookup: add comment, de-ident main path. No functional change.
tmpfs_dir_attach: add assert.

Clean up vnode lock operations pass 2:

VOP_UNLOCK(vp, flags) -> VOP_UNLOCK(vp): Remove the unneeded flags argument.

Welcome to 5.99.32.

Discussed on tech-kern.

Replace tmpfs_pool custom allocator code with a simpler layer for memory
accounting. Use wired memory (which can be limited) for meta-data, and
kmem(9) for string allocations.

Close PR/31944. Fix PR/38361 while here. OK ad@.

Enforce RLIMIT_FSIZE before VOP_WRITE. This adds support to file
system drivers where it was missing from and fixes one buggy
implementation. The arguably weird semantics of the check are
maintained (v_size vs. va_bytes, overwrite).

Stop exposing fifofs internals and leave only fifo_vnodeop_p visible.

\n, police!

branches: 1.66.2; 1.66.4;
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

Fix panic when trying to delete a directory entry (hi yamt!) by not
attempting to release a pnbuf that does not exist.

I.e. fixes "mkdir a ; unlink a/.". And actually, this was caught by the
automated tests.

Make tmpfs write fail when process file size limit is reached.

tmpfs_rename: handle hard-links correctly. Fixes PR/41236.

Implement the vnode scope and adapt tmpfs to use it.

Mailing list reference:

http://mail-index.netbsd.org/tech-kern/2009/07/04/msg005404.html

Where possible, extract the file-system's access() routine to two internal
functions: the first checking if the operation is possible (regardless of
permissions), the second checking file-system permissions, ACLs, etc.

Mailing list reference:

http://mail-index.netbsd.org/tech-kern/2009/06/21/msg005311.html

Move the implementation of vaccess() to genfs_can_access(), in line with
the other routines of the same spirit.

Adjust file-system code to use it.

Keep vaccess() for KPI compatibility and to keep element of least
surprise. A "diagnostic" message warning that vaccess() is deprecated will
be printed when it's used (obviously, only in DIAGNOSTIC kernels).

No objections on tech-kern@:

http://mail-index.netbsd.org/tech-kern/2009/06/21/msg005310.html

replace outdated comment. no functional change

plug some pnbuf leaks.

SAVENAME was not set for rename and delete as required

Patch from christos, fixes pr 41183

Invariants should be tested for with KASSERT instead of semi-pretending
that them not holding is an acceptable error condition.

Fix yet another recent crashy bug in tmpfs rename: since the source
dirent is no longer cached in lookup and we do the lookup ourselves
in rename, we are most definitely not allowed to assert that it
matches the source vnode passed as an argument. In case the source
node does not exist or has been replaced, punt with ENOENT.

Also, nuke some misleading prehistoric comments which haven't been
valid in over a year.

Fixes PR kern/41128 by Nicolas Joly

Release dvp in mknod error branch.

Nicolas Joly, PR kern/41006

branches: 1.53.2;
If fdvp is tvp, do nothing. Prevents local DoS panic described in
PR kern/38219... maybe. This is hastily concocted fix for 5.0 and
I'm not sure if it has side-effects.

Rototill all remaining file systems to use ubc_uiomove() instead
of the ubc_alloc() - uiomove() - ubc_release() dance.

branches: 1.51.2; 1.51.4; 1.51.6;
- setting the birthdate is valid in setattr.
- don't call nanotime if not needed.
- don't call tempfs_update() if tempfs_chtimes succeeded, because it just did.

branches: 1.50.2; 1.50.4;
Remove clause 3 and 4 from TNF licenses

branches: 1.49.6; 1.49.8; 1.49.10;
Drop trailing whitespace.

Remove debugging code that's no longer needed.

Replace struct lock on vnodes with a simpler lock object built on
krwlock_t. This is a step towards removing lockmgr and simplifying
vnode locking. Discussed on tech-kern.

Remove VOP_LEASE. Discussed on tech-kern.

Merge vmlocking2 to head.

branches: 1.44.2; 1.44.6;
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

Fix a race condition: in case two source paths hardlinked to the
same file were renamed simultaneously, there was a window where
directory entry cached in the vnode during lookup would be replaced
before calling rename. This lead to one directory entry getting
renamed twice and the other one getting zero renames. Do a relookup
in rename to make sure we have the correct directory entry.

Thanks go to Greg Oster for reporting the problem, helping with
debugging and thoroughly testing the patch.

Back out the tmpfs changes; there appears to be a bug lurking.

Merge from vmlocking.

branches: 1.40.2;
Borrow a clue from the vmlocking branch, and consolidate all of
the vput(9)ing in tmpfs_rmdir() in one place. No functional change
intended.

branches: 1.39.4; 1.39.6; 1.39.10; 1.39.12;
Multiple fixes for tmpfs' rename operation:

- Raise an error if renaming a file to a directory.
- Raise an error if renaming a directory to a file.
- Raise an error if renaming a directory to a non-empty directory.
- Properly allow renaming a directory to an empty directory.
The system could previously crash if the kernel had DIAGNOSTIC enabled,
as this triggered a bogus assertion.

Problem found by Geoff Wing.

branches: 1.38.2;
Merge some of the less invasive changes from the vmlocking branch:

- kthread, callout, devsw API changes
- select()/poll() improvements
- miscellaneous MT safety improvements

branches: 1.37.4; 1.37.6;
TRUE -> true, FALSE -> false

Replace the Mach-derived boolean_t type with the C99 bool type. A
future commit will replace use of TRUE and FALSE with true and false.

branches: 1.35.2;
Consistent usage of KAUTH_GENERIC_ISSUSER.

* fix locking gotchas when trying to unlink "."
* return standard EPERM when trying to unlink a directory
* reorder some checks in rmdir avoid problems if trying to rmdir ".."

jmmv ok

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: 1.32.2;
Opening a file after it has been removed (e.g. rmdir $(pwd)) has to fail.

Audit kqueue notifications. The reference behavior is taken from MFS and
is represented in the regression tests.

tmpfs_open cannot assume that the node to be open is still linked to a
directory, so remove an invalid assertion. Otherwise the kernel incorrectly
panics when accessing the current directory after it has been removed.

Truncate directory cookies to 31 bits to avoid problems exposed in Linux
binaries which cast the returned values to 64-bits and fail due to sign
expansion. More details are provided in the big comment in tmpfs.h that
describes how the new tmpfs_dircookie works.

This is a rather ugly hack that shall be fixed with a cleaner solution,
but this resolves the problem in an effective way.

Fixes kern PR/32034.