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@).

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@).

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.

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@).

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

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@).

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;
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@).

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.

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