Dust off the orphan detection code and try to make it work.

Teach LFS_ORPHAN_NEXTFREE about lfs64.

Avoid undefined behavior in *_BITMAP_FREE() macros

left shift of 1 by 31 places cannot be represented in type 'int'

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: 1.137.10;
Consistently use {,UN}MARK_VNODE macros rather than function calls.

Rename i_flag to i_state.

The similarity to i_flags has previously caused errors.

branches: 1.135.6;
Fill in some XXXs with the exact action described in them. match
lfs_valloc behaviour.

#if DIAGNOSTIC panic ---> KASSERT

Replace some #if DEBUG by this too. DEBUG is only for expensive
assertions; these are not.

branches: 1.133.2;
Remove unused <sys/tree.h>

Comments

branches: 1.131.2;
Fix minor bitrot in #if 0 or otherwise disabled code.

Fix wrong code in lfs_valloc_fixed(). It was overwriting the inode
number it was supposed to be allocating with the head of the inode
freelist, then applying the wrong test to that result. Net result:
unless the freelist was empty (in which case it would always fail),
it would in general drop a bunch of entries from the freelist.

This code seems to have been broken when the first version of lfsv2
was imported onto the perseant-lfsv2 branch in -r1.47.2.1, and
remained broken since, in spite of having been moved to lfs_rfw.c and
back and rearranged quite a bit in the meantime.

Sigh.

Found by Coverity in a rather confusing way as CID 1316545.

Use the lfs dinode accessors in place of the ufs-derived ones.
(Mostly.)

The ufs-derived ones are fake structure member macros, which are gross
and not very safe. Also, it seems that a lot of places in the lfs code
were using the ffsv1 branch of them unconditionally, and this way it's
guaranteed all those places have been updated.

Found while doing this: for non-devices, have getattr produce NODEV
in the rdev field instead of leaking the address of the first direct
block.

Fix IFILE pointer calculation when scanning freelist.

Hack up dinode usage to be 64 vs. 32 as needed. Part 1.

(This part changes the native lfs code; the ufs-derived code already
has 64 vs. 32 logic, but as aspects of it are unsafe, and don't
entirely interoperate cleanly with the lfs 64/32 stuff, pass 2 will be
rehashing that.)

Add IFILE32 and IFILE64 structures for the on-disk ifile entries.
Add and use accessors. There are also a bunch of places that cast and
I hope I've found them all...

Use accessor functions for the version field of the lfs superblock.
I thought at first maybe the cases that test the version should be
rolled into the accessors, but on the whole I think the conclusion on
that is no.

Add a new lfs header file: lfs_accessors.h.

This contains all the accessor functions and macros out of lfs.h.
Add an include of lfs_accessors.h after all uses of lfs.h... except
for code that wants to define its own struct lfs-alike that the
accessors are supposed to play along with. For these, set STRUCT_LFS
and include lfs_accessors.h after the necessary structure has been
defined, so that lfs_accessors.h can emit functions in terms of it.

More lfs superblock accessors.
(This changes the rest of the code over; all the accessors were
already added.)

The difference between this commit and the previous one is arbitrary,
but the previous one passed the regression tests on its own so I'm
keeping it separate to help with any bisections that might be needed
in the future.

Switch to accessor functions for elements of the LFS on-disk
superblock. This will allow switching between 32/64 bit forms on the
fly; it will also allow handling LFS_EI reasonably tidily. (That
currently doesn't work on the superblock.)

It also gets rid of cpp abuse in the form of fake structure member
macros.

Also, instead of doing sleep/wakeup on &lfs_avail and &lfs_nextseg
inside the on-disk superblock, add extra elements to the in-memory
struct lfs for this. (XXX: these should be changed to condvars, but
not right now)

XXX: this migrates a structure needed by the lfs code in libsa (struct
salfs) into lfs.h, where it doesn't belong, but for the time being
this is necessary in order to allow the accessors (and the various
lfs macros and other goop that relies on them) to compile.

Don't cast the return value of malloc.

Change lfs from hash table to vcache.

- Change lfs_valloc() to return an inode number and version instead of
a vnode and move lfs_ialloc() and lfs_vcreate() to new lfs_init_vnode().

- Add lfs_valloc_fixed() to allocate a known inode, used by kernel
roll forward.

- Remove lfs_*ref(), these functions cannot coexist with vcache and
their commented behaviour is far away from their implementation.

- Add the cleaner lwp and blockinfo to struct ulfsmount so lfs_loadvnode()
may use hints from the cleaner.

- Remove vnode locks from ulfs_lookup() like we did with ufs_lookup().

branches: 1.119.6;
Add more of the bits for supporting quotas.

Add lfs_kernel.h for declarations that don't need to be exposed to userland.

lfs currently has the following headers:
lfs.h - on-disk structures and stuff needed for userlevel tools
lfs_inode.h - additional restricted materials for userlevel tools
that operate the fs (newfs_lfs, fsck_lfs, lfs_cleanerd)
lfs_kernel.h - stuff needed only in the kernel

and the following legacy headers that are expected to be mopped up and
folded into one of the above:
lfs_extern.h - function prototypes
ulfs_bswap.h - endian-independent support
ulfs_dinode.h - now contains very little
ulfs_dirhash.h - dirhash support
ulfs_extattr.h - extattr support
ulfs_extern.h - more function prototypes
ulfs_inode.h - assorted kernel-only declarations
ulfs_quota.h - quota support
ulfs_quota1.h - more quota support
ulfs_quota2.h - more quota support
ulfs_quotacommon.h - more quota support
ulfsmount.h - legacy copy of ufsmount material

branches: 1.117.2;
Prefix most of the cpp macros with lfs_ and LFS_ to avoid conflicts with ffs.
This was done so that boot blocks that want to compile both FFS and LFS in
the same file work.

Split lfs from ufs step 4:

Massedit all ufs symbols to be "ulfs" instead, to make sure there are
no conflicts with ufs. Confirmed with grep.

(This required changing a few comments that maybe should have been
left alone to say "ulfs", but we'll survive that.)

Split lfs from ufs step 3: rearrange config stuff.
Add new options:
LFS_EI
LFS_DIRHASH
LFS_EXTATTR
LFS_EXTATTR_AUTOSTART
LFS_QUOTA
LFS_QUOTA2

and update code referring to the corresponding FFS and UFS config
symbols to use the LFS versions. Disable the one extant reference
to APPLE_UFS in the ulfs files. Use opt_lfs.h only, not opt_ffs.h.

Split lfs from ufs, part 2:

Change all <ufs/ufs/foo.h> includes to <ufs/lfs/ulfs_foo.h>.

Stuff UFS_ in front of a few of ufs's symbols to reduce namespace
pollution. Specifically:
ROOTINO -> UFS_ROOTINO
WINO -> UFS_WINO
NXADDR -> UFS_NXADDR
NDADDR -> UFS_NDADDR
NIADDR -> UFS_NIADDR
MAXSYMLINKLEN -> UFS_MAXSYMLINKLEN
MAXSYMLINKLEN_UFS[12] -> UFS[12]_MAXSYMLINKLEN (for consistency)

Sort out ext2fs's misuse of NDADDR and NIADDR; fortunately, these have
the same values in ext2fs and ffs.

No functional change intended.

branches: 1.112.2;
Pass t_renamerace and t_rmdirrace tests.

Adapt dholland@'s fix to ufs_rename to fix PR kern/43582. Address several
other MP locking issues discovered during the course of investigating the
same problem.

Removed extraneous vn_lock() calls on the Ifile, since the Ifile writes
are controlled by the segment lock.

Fix PR kern/45982 by deemphasizing the estimate of how much metadata
will fill the empty space on disk when the disk is nearly empty
(t_renamerace crates a lot of inode blocks on a tiny empty disk).

branches: 1.111.2; 1.111.6; 1.111.8;
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: 1.110.6;
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.

branches: 1.109.2; 1.109.4;
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

Move declaration of ufs_hashlock into <ufs/ufs_extern.h> from each c source.

Remove clause 3 and 4 from TNF licenses

branches: 1.106.6; 1.106.8; 1.106.10;
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.

Merge vmlocking2 to head.

Fix a use of lfs_truncate() inside an #ifdef notyet (so no resulting change);
lfs_truncate() has lost its lwp argument.

branches: 1.103.4; 1.103.6; 1.103.8; 1.103.10;
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.

Merge ffs locking & brelse changes from the vmlocking branch.

branches: 1.101.6; 1.101.8; 1.101.10;
Move `struct dquot' and its supporting functions from quota.h to ufs_quota.c.

- Make quota-internal functions static.
- Clean up declarations in quota.h and ufs_extern.h. quota.h now has the
description of quota criterions, on-disk structure, user-kernel interface and
declaration of init/done functions. All ufs quota related function
prototypes go to ufs_extern.h.
- New functions ufsquota_init() and ufsquota_free() create or destroy the
quota fields of `struct inode'.
- chkdq() and chkiq() always update the quota fields of `struct inode' first.
- Only ufs_access() explicitely calls getinoquota().

No objections on tech-kern@

branches: 1.100.6; 1.100.8;
Replace some uses of lockmgr() / simplelocks.

__unused removal on arguments; approved by core.

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

branches: 1.97.2; 1.97.4;
Changes to help the roll-forward agent, to wit:

* Mark being-deleted files in the Ifile so we can finish deleting them
at fs mount time.
* Flag the Ifile with "cleaner must clean" when writers are waiting for
the cleaner, rather than relying solely on the cleaner's estimation of
whether it should clean or not.
* Note partial segments written by a user agent (in particular,
fsck_lfs) so that repeated rolls forward don't interfere with one
another.
* Add a new fcntl, LFCNPASS, that allows the log to wrap exactly once,
for better testing of the validity of checkpoints.
* Keep track of the on-disk nlink count when cleaning, so that we don't
partially complete directory operations while cleaning.
* Ensure that every single Ifile inode write represents a consistent
view of the filesystem. In particular, the accounting for the segment
we are writing the inode into must be correct, and the accounting for
the segment that inode used to reside in must be correct. Rather than
just rewriting the inode if we wrote it wrong, rewrite the necessary
ifile blocks before writing the inode so we never write it wrong.
* Don't unmark any VDIROP vnodes if we haven't written them to disk,
avoiding yet another problem with the "wait for the cleaner" error
return from lfs_putpages().

Also, move the last callback to an aiodone call, so we no longer do any
memory management from interrupt context.

Separate the (non-working) LFS kernel roll-forward code into its own file,
lfs_rfw.c.

Protect lfs_order_freelist() with the segment lock.

branches: 1.94.4;
integrate kauth.

Fixes to address the "vinvalbuf: dirty blocks" panic that can occur when
many inodes are cleaned at once. Make sure that we write all the pages
on vnodes that are being flushed, even if we don't think there's room;
drain v_numoutput before lfs_vflush() completes.

Also, don't allow a vnode that is in the process of being cleaned to be
chosen by getnewvnode(); this avoids a segment accounting panic in the case
that a large number of inodes are fed to lfs_markv() all at once.

Introduce another per-filesystem parameter, lfs_resvseg, to separate the
notion of "how many segments are reserved for the cleaner" from that of
"how many segments are not counted in lfs_bfree". The default value
used for existing filesystems is the same as the previous implicit value
of (lfs_minfreeseg / 2 + 1), modulo some sanity checking.

Count pending dirops on a per-filesystem basis, since once we start
writing them we can't stop until we're done. This seems to help stave off
the "no clean segments" panic in the case of filling the filesystem with
directories and small files (e.g. simultaneously unpacking more copies of
pkgsrc than will fit).

Add an explicit list initialization that was missing from my last commit.

Postpone the segment accounting changes coming from truncation until the
inode that makes those changes valid is either written to disk by
lfs_writeinode() or discarded by lfs_vfree().

A couple of locking fixes are also included as well.

Fix a fencepost error in the bitmap handling in extend_ifile(), and another
in lfs_freelist_prev().

Optimize the free list search a little more; in particular use words
instead of bytes for the index, and never search below fs->lfs_freehd.

Fix a bug in the previous version of the search (an erroneous assumption
that ino_t was signed).

Free the bitmap when we unmount the filesystem.

Keep the free list ordered. This solves a problem first pointed out to me
by Michel Oey, in which an aged LFS writes up to an extra Ifile block for
every file created; and paves the way for the truncation of the Ifile when
many files are deleted.

branches: 1.86.4; 1.86.6; 1.86.8; 1.86.10; 1.86.12;
merge ktrace-lwp.

merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.84.2;
64 bit inode changes.

branches: 1.83.2;
- sprinkle const
- avoid shadow variables.

Keep per-inode, per-fs, and subsystem-wide counts of blocks allocated through
lfs_balloc(), and use that to estimate the number of dirty pages belonging
to LFS (subsystem or filesystem). This is almost certainly wrong for
the case of a large mmap()ed region, but the accounting is tighter than
what we had before, and performs much better in the typical case of pages
dirtied through write().

Use splay trees, rather than a hash table, to manage the accounting of
blocks allocated through VOP_BALLOC() for pages to be written to disk.
This accounting no longer takes a noticeable fraction of the system CPU.

Consolidate the hash table we use to maintain the integrity of lfs_avail
into a single, system-wide table, rather than having a separate hash table
per inode. Significantly reduces the "system" cpu usage of your average
file write.

Keep track of the highest block held by an LFS inode, so that we can
be assured that the last byte of a file is always allocated. Previously
a file extension could cause the filesystem to be flushed, writing an
inconsistent inode to disk. Although this condition would be corrected
the next time blocks were written to disk, an intervening crash would leave
the filesystem in an inconsistent state, leaving fsck_lfs to complain
of an inode "partially truncated".

Protect various per-fs structures with fs->lfs_interlock simple_lock, to
improve behavior in the multiprocessor case. Add debugging segment-lock
assertion statements.

Make LFS dirops get their vnode first, before incrementing the dirop count,
to prevent a deadlock trying to call VOP_PUTPAGES() on a VDIROP vnode.
This can happen when a stacked filesystem is mounted on top of an LFS: an
LFS dirop needs to get a vnode, which is available from the upper layer.
The corresponding lower layer vnode, however, is VDIROP, so the upper layer
can't be cleaned out since its VOP_PUTPAGES() is passed through to the lower
layer, which waits for dirops to drain before it can proceed. Deadlock.

Tweak ufs_makeinode() and ufs_mkdir() to pass the a_vpp argument through
to VOP_VALLOC().

Partially addresses PR # 26043, though it probably does not completely fix
the problem described there.

branches: 1.76.2;
Straighten out the maze of ifdefs. Instead, consolidate all the debugging
stuff under '#ifdef DEBUG', and use sysctl knobs to turn on/off particular
parts of the debugging reporting (if DEBUG is enabled). Re-enable the LFS
statistics in sysctl, while I'm there. A bit of a rototill.

nuke trailing whitespace

Various minor LFS improvements:

* Note when lfs_putpages(9) thinks it is not going to be writing any
pages before calling genfs_putpages(9). This prevents a situation in
which blocks can be queued for writing without a segment header.
* Correct computation of NRESERVE(), though it is still a gross
overestimate in most cases. Note that if NRESERVE() is too high, it
may be impossible to create files on the filesystem. We catch this
case on filesystem mount and refuse to mount r/w.
* Allow filesystems to be mounted whose block size is == MAXBSIZE.
* Somewhere along the line, ufs_bmaparray(9) started mangling UNWRITTEN
entries in indirect blocks again, triggering a failed assertion "daddr
<= LFS_MAX_DADDR". Explicitly convert to and from int32_t to correct
this.
* Add a high-water mark for the number of dirty pages any given LFS can
hold before triggering a flush. This is settable by sysctl, but off
(zero) by default.
* Be more careful about the MAX_BYTES and MAX_BUFS computations so we
shouldn't see "please increase to at least zero" messages.
* Note that VBLK and VCHR vnodes can have nonzero values in di_db[0]
even though their v_size == 0. Don't panic when we see this.
* Change lfs_bfree to a signed quantity. The manner in which it is
processed before being passed to the cleaner means that sometimes it
may drop below zero, and the cleaner must be aware of this.
* Never report bfree < 0 (or higher than lfs_dsize) through
lfs_statvfs(9). This prevents df(1) from ever telling us that our full
filesystems have 16TB free.
* Account space allocated through lfs_balloc(9) that does not have
associated buffer headers, so that the pagedaemon doesn't run us out
of segments.
* Return ENOSPC from lfs_balloc(9) when bfree drops to zero.
* Address a deadlock in lfs_bmapv/lfs_markv when the filesystem is being
unmounted. Because vfs_busy() is a shared lock, and
lfs_bmapv/lfs_markv mark the filesystem vfs_busy(), the cleaner can be
holding the lock that umount() is blocking on, then try to vfs_busy()
again in getnewvnode().

branches: 1.73.4; 1.73.6;
Add a new flag, IN_MODIFY. This is like IN_UPDATE|IN_CHANGE, but unlike
setting those flags, it does not cause the inode to be written in the periodic
sync. This is used for writes to special files (devices and named pipes) and
FIFOs.

Do not preemptively sync updates to access times and modification times. They
are now updated in the inode only opportunistically, or when the file or device
is closed. (Really, it should be delayed beyond close, but this is enough to
help substantially with device nodes.)

And the most amusing part:
Trickle sync was broken on both FFS and ext2fs, in different ways. In FFS, the
periodic call to VFS_SYNC(MNT_LAZY) was still causing all file data to be
synced. In ext2fs, it was causing the metadata to *not* be synced. We now
only call VOP_UPDATE() on the node if we're doing MNT_LAZY. I've confirmed
that we do in fact trickle correctly now.

branches: 1.72.4;
cleanup IN_ADIROP/VDIROP handling a little.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22364, verified by myself.

- protect global resource counts with lfs_subsys_lock.
- clean up scattered externs a little.

branches: 1.69.2;
Back out the lwp/ktrace changes. They contained a lot of colateral damage,
and need to be examined and discussed more.

Undo part of the ktrace/lwp changes. In particular:
* Remove the "lwp *" argument that was added to vget(). Turns out
that nothing actually used it!
* Remove the "lwp *" arguments that were added to VFS_ROOT(), VFS_VGET(),
and VFS_FHTOVP(); all they did was pass it to vget() (which, as noted
above, didn't use it).
* Remove all of the "lwp *" arguments to internal functions that were added
just to appease the above.

Pass lwp pointers throughtout the kernel, as required, so that the lwpid can
be inserted into ktrace records. The general change has been to replace
"struct proc *" with "struct lwp *" in various function prototypes, pass
the lwp through and use l_proc to get the process pointer when needed.

Bump the kernel rev up to 1.6V

Add support for UFS2. UFS2 is an enhanced FFS, adding support for
64 bit block pointers, extended attribute storage, and a few
other things.

This commit does not yet include the code to manipulate the extended
storage (for e.g. ACLs), this will be done later.

Originally written by Kirk McKusick and Network Associates Laboratories for
FreeBSD.

Add simple_lock protection for lfs_seglock and lfs_subsys_pages; these will
be expanded to cover other per-fs and subsystem-wide data as well.

Fix a case of IN_MODIFIED being set without updating lfs_uinodes, resulting
in a "lfs_uinodes < 0" panic.

Fix a deadlock in lfs_putpages arising from the need to busy all pages in a
block; unbusy any that had already been busied before starting over.

Tabify, and fix some comment alignment problems.

Add code to UBCify LFS. This is still behind "#ifdef LFS_UBC" for now
(there are still some details to work out) but expect that to go
away soon. To support these basic changes (creation of lfs_putpages,
lfs_gop_write, mods to lfs_balloc) several other changes were made, to
wit:

* Create a writer daemon kernel thread whose purpose is to handle page
writes for the pagedaemon, but which also takes over some of the
functions of lfs_check(). This thread is started the first time an
LFS is mounted.

* Add a "flags" parameter to GOP_SIZE. Current values are
GOP_SIZE_READ, meaning that the call should return the size of the
in-core version of the file, and GOP_SIZE_WRITE, meaning that it
should return the on-disk size. One of GOP_SIZE_READ or
GOP_SIZE_WRITE must be specified.

* Instead of using malloc(...M_WAITOK) for everything, reserve enough
resources to get by and use malloc(...M_NOWAIT), using the reserves if
necessary. Use the pool subsystem for structures small enough that
this is feasible. This also obsoletes LFS_THROTTLE.

And a few that are not strictly necessary:

* Moves the LFS inode extensions off onto a separately allocated
structure; getting closer to LFS as an LKM. "Welcome to 1.6O."

* Unified GOP_ALLOC between FFS and LFS.

* Update LFS copyright headers to correct values.

* Actually cast to unsigned in lfs_shellsort, like the comment says.

* Keep track of which segments were empty before the previous
checkpoint; any segments that pass two checkpoints both dirty and
empty can be summarily cleaned. Do this. Right now lfs_segclean
still works, but this should be turned into an effectless
compatibility syscall.

make these compilable with lfs debug options.
(follow daddr_t change)

XXX maybe segment number should be 64bit.

Use PRId64 instead of hard coding "%lld" to fix build problems under
LP64 ports.

Fix printf() format strings problems caused by "daddr_t" change.

Bump daddr_t to 64 bits. Replace it with int32_t in all places where
it was used on-disk, so that on-disk formats remain the same.
Remove ufs_daddr_t and ufs_lbn_t for the time being.

use lfs_unmark_vnode instead of duplicated code fragments.

make sure i_lfs_fragsize is initialized.
fix panic "lfs_writefile: more than one fragment!"
PR 18974.

Phase one of my three-phase plan to make LFS play nice with UBC, and bug-fixes
I found while making sure there weren't any new ones.

* Make the write clusters keep track of the buffers whose blocks they contain.
This should make it possible to (1) write clusters using a page mapping
instead of malloc, if desired, and (2) schedule blocks for rewriting
(somewhere else) if a write error occurs. Code is present to use
pagemove() to construct the clusters but that is untested and will go away
anyway in favor of page mapping.
* DEBUG now keeps a log of Ifile writes, so that any lingering instances of
the "dirty bufs" problem can be properly debugged.
* Keep track of whether the Ifile has been dirtied by various routines that
can be called by lfs_segwrite, and loop on that until it is clean, for
a checkpoint. Checkpoints need to be squeaky clean.
* Warn the user (once) if the Ifile grows larger than is reasonable for their
buffer cache. Both lfs_mountfs and lfs_unmount check since the Ifile can
grow.
* If an inode is not found in a disk block, try rereading the block, under
the assumption that the block was copied to a cluster and then freed.
* Protect WRITEINPROG() with splbio() to fix a hang in lfs_update.

Correct free list tail pointer, when adding blocks of new inodes to v2
filesystems. Should fix PR #14408.

use the new compatibility routines to allow mmap() to work
(in the same non-coherent fashion that it worked pre-UBC)
until someone has time to do it the right way.

add spaces for KNF. confirmed to produce identical objects.

add RCSID

branches: 1.51.2;
initialize the vnode's copy of the size in lfs_ialloc().

don't depend on other headers to include sys/proc.h for us.

a whole bunch of changes to improve performance and robustness under load:

- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.

The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.

branches: 1.48.2;
Merge the short-lived perseant-lfsv2 branch into the trunk.

Kernels and tools understand both v1 and v2 filesystems; newfs_lfs
generates v2 by default. Changes for the v2 layout include:

- Segments of non-PO2 size and arbitrary block offset, so these can be
matched to convenient physical characteristics of the partition (e.g.,
stripe or track size and offset).

- Address by fragment instead of by disk sector, paving the way for
non-512-byte-sector devices. In theory fragments can be as large
as you like, though in reality they must be smaller than MAXBSIZE in size.

- Use serial number and filesystem identifier to ensure that roll-forward
doesn't get old data and think it's new. Roll-forward is enabled for
v2 filesystems, though not for v1 filesystems by default.

- The inode free list is now a tailq, paving the way for undelete (undelete
is not yet implemented, but can be without further non-backwards-compatible
changes to disk structures).

- Inode atime information is kept in the Ifile, instead of on the inode;
that is, the inode is never written *just* because atime was changed.
Because of this the inodes remain near the file data on the disk, rather
than wandering all over as the disk is read repeatedly. This speeds up
repeated reads by a small but noticeable amount.

Other changes of note include:

- The ifile written by newfs_lfs can now be of arbitrary length, it is no
longer restricted to a single indirect block.

- Fixed an old bug where ctime was changed every time a vnode was created.
I need to look more closely to make sure that the times are only updated
during write(2) and friends, not after-the-fact during a segment write,
and certainly not by the cleaner.

branches: 1.47.2; 1.47.4;
use _KERNEL_OPT

branches: 1.46.2;
Get rid of some old unnecessary code that cleared B_NEEDCOMMIT from buffers in
lfs_writeseg (possibly after they had been freed).

If MALLOCLOG is defined, make lfs_newbuf and lfs_freebuf pass along the
caller's file and line to _malloc and _free.

Initial integration of the Unified Buffer Cache project.

If LFS_DO_ROLLFORWARD is defined, roll forward from the older checkpoint
on mount, through the newer checkpoint and on through any newer
partial-segments that may have been written but not checkpointed because
of an intervening crash.

LFS_DO_ROLLFORWARD is not defined by default.

Various bug-fixes to LFS, to wit:


Kernel:

* Add runtime quantity lfs_ravail, the number of disk-blocks reserved
for writing. Writes to the filesystem first reserve a maximum amount
of blocks before their write is allowed to proceed; after the blocks
are allocated the reserved total is reduced by a corresponding amount.

If the lfs_reserve function cannot immediately reserve the requested
number of blocks, the inode is unlocked, and the thread sleeps until
the cleaner has made enough space available for the blocks to be
reserved. In this way large files can be written to the filesystem
(or, smaller files can be written to a nearly-full but thoroughly
clean filesystem) and the cleaner can still function properly.

* Remove explicit switching on dlfs_minfreeseg from the kernel code; it
is now merely a fs-creation parameter used to compute dlfs_avail and
dlfs_bfree (and used by fsck_lfs(8) to check their accuracy). Its
former role is better assumed by a properly computed dlfs_avail.

* Bounds-check inode numbers submitted through lfs_bmapv and lfs_markv.
This prevents a panic, but, if the cleaner is feeding the filesystem
the wrong data, you are still in a world of hurt.

* Cleanup: remove explicit references of DEV_BSIZE in favor of
btodb()/dbtob().

lfs_cleanerd:

* Make -n mean "send N segments' blocks through a single call to
lfs_markv". Previously it had meant "clean N segments though N calls
to lfs_markv, before looking again to see if more need to be cleaned".
The new behavior gives better packing of direct data on disk with as
little metadata as possible, largely alleviating the problem that the
cleaner can consume more disk through inefficient use of metadata than
it frees by moving dirty data away from clean "holes" to produce
entirely clean segments.

* Make -b mean "read as many segments as necessary to write N segments
of dirty data back to disk", rather than its former meaning of "read
as many segments as necessary to free N segments worth of space". The
new meaning, combined with the new -n behavior described above,
further aids in cleaning storage efficiency as entire segments can be
written at once, using as few blocks as possible for segment summaries
and inode blocks.

* Make the cleaner take note of segments which could not be cleaned due
to error, and not attempt to clean them until they are entirely free
of dirty blocks. This prevents the case in which a cleanerd running
with -n 1 and without -b (formerly the default) would spin trying
repeatedly to clean a corrupt segment, while the remaining space
filled and deadlocked the filesystem.

* Update the lfs_cleanerd manual page to describe all the options,
including the changes mentioned here (in particular, the -b and -n
flags were previously undocumented).

fsck_lfs:

* Check, and optionally fix, lfs_avail (to an exact figure) and
lfs_bfree (within a margin of error) in pass 5.

newfs_lfs:

* Reduce the default dlfs_minfreeseg to 1/20 of the total segments.

* Add a warning if the sgs disklabel field is 16 (the default for FFS'
cpg, but not usually desirable for LFS' sgs: 5--8 is a better range).

* Change the calculation of lfs_avail and lfs_bfree, corresponding to
the kernel changes mentioned above.

mount_lfs:

* Add -N and -b options to pass corresponding -n and -b options to
lfs_cleanerd.

* Default to calling lfs_cleanerd with "-b -n 4".


[All of these changes were largely tested in the 1.5 branch, with the
idea that they (along with previous un-pulled-up work) could be applied
to the branch while it was still in ALPHA2; however my test system has
experienced corruption on another filesystem (/dev/console has gone
missing :^), and, while I believe this unrelated to the LFS changes, I
cannot with good conscience request that the changes be pulled up.]

Clean up accounting of lfs_uinodes (dirty but unwritten inodes).

Make lfs_uinodes a signed quantity for debugging purposes, and set it to
zero as fs mount time.

Enclose setting/clearing of the dirty flags (IN_MODIFIED, IN_ACCESSED,
IN_CLEANING) in macros, and use those macros everywhere. Make
LFS_ITIMES use these macros; updated the ITIMES macro in inode.h to know
about this. Make ufs_getattr use ITIMES instead of FFS_ITIMES.

i_lfs_effnblks fixes. Put debugging printfs under #ifdef DEBUG_LFS.

Rearrange code around getnewvnode as was already done for ffs, to avoid
locking against oneself because getnewvnode recycles a softdep-using vnode.

remove include of <vm/vm.h> and <uvm/uvm_extern.h>

Fixes associated with filling an LFS:

Change the space computation to appear to change the size of the *disk*
rather than the *bytes used* when more segment summaries and inode
blocks are written. Try to estimate the amount of space that these will
take up when more files are written, so the disk size doesn't change too
much.

Regularize error returns from lfs_valloc, lfs_balloc, lfs_truncate: they
now fail entirely, rather than succeeding half-way and leaving the fs in
an inconsistent state.

Rewrite lfs_truncate, mostly stealing from ffs_truncate. The old
lfs_truncate had difficulty truncating a large file to a non-zero size
(indirect blocks were not handled appropriately).

Unmark VDIROP on fvp after ufs_remove, ufs_rmdir, so these can be
reclaimed immediately: this vnode would not be written to disk again
anyway if the removal succeeded, and if it failed, no directory
operation occurred.

ufs_makeinode and ufs_mkdir now remove IN_ADIROP on error.

fix my own typo, grr....

Read i_ffs_gen from the version number in the Ifile during lfs_valloc,
instead of keeping it always == 1. (The ifile version number is
increased on vfree.) May address PR #7213, but I haven't been able to
test thoroughly enough to say for sure.

Update lfs_vunref for the fact that now a vnode can be locked with no
references (locked for VOP_INACTIVE at the end of vrele) and it's okay.
Check the return value of lfs_vref where appropriate.
Fixes PR #s 10285 and 10352.

branches: 1.34.2;
Protect inode free list with seglock, instead of separate lock, so that
the head of the inode free list (on the superblock) always matches the
rest of the free list (in the ifile).

Protect lfs_fragextend with seglock, to prevent the segment byte count
fudging from making its way to disk.

Don't try to inactivate dirop vnodes that are still in the middle of
their dirop (may address PR#10285).

update for IN_ACCESSED changes

branches: 1.32.2;
Prevent dirops from getting around lfs_check and wedging the buffer cache.
All the dirop vnops now mark the inodes with a new flag, IN_ADIROP, which
is removed as soon as the dirop is done (as opposed to VDIROP which stays
until the file is written). To address one issue raised in PR#9357.

Changes to stabilize LFS. The first two of these should also apply to the
1.4 branch.

* Use a separate per-fs lock, instead of ufs_hashlock, to protect the Inode
free list. This seems to prevent the "lockmgr: %d, not exclusive lock holder
%d, unlocking" message I was mis-attributing last night to an unlocked vnode
being passed to vrele.

* Change calling semantics of lfs_ifind, to give better error reporting:
If fed a struct buf, it can report the block number of the offending inode
block as well as the inode number.

* Back out rev 1.10 of lfs_subr.c, since the replacement code was slightly
uglier while being functionally identical.

* Make lfs_vunref use the same free list convention as vrele/vput, so that
vget does not remove vnodes from a hash list they are not on.

Fix error returns on lfs vnops so that locks and reference counts are
preserved. Handle dirop accounting in lfs_vfree for this case as well.
May address PR#8823.

Add Kirk McKusick's soft updates code to the trunk. Not enabled by
default, as the copyright on the main file (ffs_softdep.c) is such
that is has been put into gnusrc. options SOFTDEP will pull this
in. This code also contains the trickle syncer.

Bump version number to 1.4O

Back out my patch of the 8th (to address unreferenced inode problem).
Apparently this needs more thought.

If ifile blocks were written before dirops were complete, and then the
system crashed, inodes could be allocated that were not referenced. (Though
not a serious problem, it evidences itself in phase 4 of fsck_lfs.) Fix
this by marking if_daddr with UNASSIGNED before the inodes are actually
written; at mount time the ifile is checked for UNASSIGNED entries and
any that are found are linked back into the free list. (The latter
functionality should move into the roll-forward agent when it materializes.)

branches: 1.26.2;
Address ufs_hashlock/ufs_ihashins protocol bug, discovered while doing a
post-mortem of a production machine. Also, take the active dirop
count off of the fs and make it global (since it is measuring a global
resource) and tie the threshold value LFS_MAXDIROP to desiredvnodes.

branches: 1.25.2; 1.25.4; 1.25.6;
Make changes that will allow an LFS filesystem to be used as the root
filesystem. In particular,

- Fix mknod deadlock, described in PR 8172.
- Enable lfs_mountroot.
- Make lfs_writevnodes treat filesystems mounted on lfs device nodes properly,
by flushing that device rather than trying to add blocks to the device inode.

This, in combination with lfs boot blocks, will allow operation of an all-lfs
system.

Modify file systems to deal with struct lock in struct vnode. All leaf
fs's other than nfs use genfs_lock() for locking.

Modify lookup routines to set PDIRUNLOCK when they unlock the parrent.

squash some compiler warnings on debug printfs by casting to int

Minor changes to the segment live bytes calculation. In particular, fixed
a bug in fragment extension that could run the count negative. Also, don't
overcount for inodes, and don't count segment summaries. Thus, for empty
segments the live bytes count should now be exactly zero.

Other half of the ufs_hashlock locking fix (oops)

Fix locking panic on ufs_hashlock

Take out the `#ifdef USE_UFSHASH'; use ufs_hashlock to lock the inode free
list instead of free_lock.

branches: 1.18.2;
completely remove Mach VM support. all that is left is the all the
header files as UVM still uses (most of) these.

New sources should leave the LFS in a more-or-less working state. Changes
include:

- DIROP segregation is enabled, and greater care is taken
to make sure that a checkpoint completes. Fsck is not
needed to remount the filesystem.
- Several checks to make sure that the LFS subsystem does not
overuse various resources (memory, in particular).
- The cleaner routines, lfs_markv in particular, are completely
rewritten. A buffer overflow is removed. Greater care is taken
to ensure that inodes come from where lfs_cleanerd say they come
from (so we know nothing has changed since lfs_bmapv was called).
- Fragment allocation is fixed, so that writes beyond end-of-file
do the right thing.

Use DINODE_SIZE rather than sizeof(struct dinode).

Use the pool allocator and the "nointr" pool page allocator for LFS inodes.

Always include fifos; "not an option any more".

Protect various config(8)-generated files from inclusion while
building LKMs. Fixes PR 5557.

Use the newly-defined opt_quota.h.

Merge with Lite2 + local changes

add UVM stuff.

Don't cast 64bit (off_t) file sizes to vm_offset_t (32bit on many
architectures), truncate them intelligently instead.
The truncation is done centralized in vnode_pager.c.
This prevents from wrap-over effects when parts of large (>2^32 byte) files
are mmapped.
Don't allow to mmap above the numerical range of vm_offset_t.
This is considered a temporary solution until the vm system handles the
object sizes/offsets more cleanly.

Add support for ext2fs, this needed a few modifications to ufs/ufs/inode.h:
- added an "union inode_ext" to struct inode, for the per-fs extentions.
For now only ext2fs uses it.
- i_din is now an union:
union {
struct dinode ffs_din; /* 128 bytes of the on-disk dinode. */
struct ext2fs_dinode e2fs_din; /* 128 bytes of the on-disk dinode. */
} i_din
Added a lot of #define i_ffs_* and i_e2fs_* to access the fields.
- Added two macros: FFS_ITIMES and EXT2FS_ITIMES. ITIMES calls the rigth
macro, depending on the time of the inode. ITIMES is used where necessary,
FFS_ITIMES and EXT2FS_ITIMES in other places.

Just increment the generation count. Using the time is bogus and defeats
fsirand(8).

branches: 1.6.6;
revert previous kprintf changes

printf -> kprintf, sprintf -> ksprintf

Appease gcc: unused variables if !QUOTA

lfs prototypes

New RCS ID's, take two. they're more aesthecially pleasant, and use 'NetBSD'

branches: 1.1.1;
Update to 4.4-Lite fs code, with local changes.

Avoid undefined behavior in *_BITMAP_FREE() macros

left shift of 1 by 31 places cannot be represented in type 'int'

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: 1.137.10;
Consistently use {,UN}MARK_VNODE macros rather than function calls.

Rename i_flag to i_state.

The similarity to i_flags has previously caused errors.

branches: 1.135.6;
Fill in some XXXs with the exact action described in them. match
lfs_valloc behaviour.

#if DIAGNOSTIC panic ---> KASSERT

Replace some #if DEBUG by this too. DEBUG is only for expensive
assertions; these are not.

branches: 1.133.2;
Remove unused <sys/tree.h>

Comments

branches: 1.131.2;
Fix minor bitrot in #if 0 or otherwise disabled code.

Fix wrong code in lfs_valloc_fixed(). It was overwriting the inode
number it was supposed to be allocating with the head of the inode
freelist, then applying the wrong test to that result. Net result:
unless the freelist was empty (in which case it would always fail),
it would in general drop a bunch of entries from the freelist.

This code seems to have been broken when the first version of lfsv2
was imported onto the perseant-lfsv2 branch in -r1.47.2.1, and
remained broken since, in spite of having been moved to lfs_rfw.c and
back and rearranged quite a bit in the meantime.

Sigh.

Found by Coverity in a rather confusing way as CID 1316545.

Use the lfs dinode accessors in place of the ufs-derived ones.
(Mostly.)

The ufs-derived ones are fake structure member macros, which are gross
and not very safe. Also, it seems that a lot of places in the lfs code
were using the ffsv1 branch of them unconditionally, and this way it's
guaranteed all those places have been updated.

Found while doing this: for non-devices, have getattr produce NODEV
in the rdev field instead of leaking the address of the first direct
block.

Fix IFILE pointer calculation when scanning freelist.

Hack up dinode usage to be 64 vs. 32 as needed. Part 1.

(This part changes the native lfs code; the ufs-derived code already
has 64 vs. 32 logic, but as aspects of it are unsafe, and don't
entirely interoperate cleanly with the lfs 64/32 stuff, pass 2 will be
rehashing that.)

Add IFILE32 and IFILE64 structures for the on-disk ifile entries.
Add and use accessors. There are also a bunch of places that cast and
I hope I've found them all...

Use accessor functions for the version field of the lfs superblock.
I thought at first maybe the cases that test the version should be
rolled into the accessors, but on the whole I think the conclusion on
that is no.

Add a new lfs header file: lfs_accessors.h.

This contains all the accessor functions and macros out of lfs.h.
Add an include of lfs_accessors.h after all uses of lfs.h... except
for code that wants to define its own struct lfs-alike that the
accessors are supposed to play along with. For these, set STRUCT_LFS
and include lfs_accessors.h after the necessary structure has been
defined, so that lfs_accessors.h can emit functions in terms of it.

More lfs superblock accessors.
(This changes the rest of the code over; all the accessors were
already added.)

The difference between this commit and the previous one is arbitrary,
but the previous one passed the regression tests on its own so I'm
keeping it separate to help with any bisections that might be needed
in the future.

Switch to accessor functions for elements of the LFS on-disk
superblock. This will allow switching between 32/64 bit forms on the
fly; it will also allow handling LFS_EI reasonably tidily. (That
currently doesn't work on the superblock.)

It also gets rid of cpp abuse in the form of fake structure member
macros.

Also, instead of doing sleep/wakeup on &lfs_avail and &lfs_nextseg
inside the on-disk superblock, add extra elements to the in-memory
struct lfs for this. (XXX: these should be changed to condvars, but
not right now)

XXX: this migrates a structure needed by the lfs code in libsa (struct
salfs) into lfs.h, where it doesn't belong, but for the time being
this is necessary in order to allow the accessors (and the various
lfs macros and other goop that relies on them) to compile.

Don't cast the return value of malloc.

Change lfs from hash table to vcache.

- Change lfs_valloc() to return an inode number and version instead of
a vnode and move lfs_ialloc() and lfs_vcreate() to new lfs_init_vnode().

- Add lfs_valloc_fixed() to allocate a known inode, used by kernel
roll forward.

- Remove lfs_*ref(), these functions cannot coexist with vcache and
their commented behaviour is far away from their implementation.

- Add the cleaner lwp and blockinfo to struct ulfsmount so lfs_loadvnode()
may use hints from the cleaner.

- Remove vnode locks from ulfs_lookup() like we did with ufs_lookup().

branches: 1.119.6;
Add more of the bits for supporting quotas.

Add lfs_kernel.h for declarations that don't need to be exposed to userland.

lfs currently has the following headers:
lfs.h - on-disk structures and stuff needed for userlevel tools
lfs_inode.h - additional restricted materials for userlevel tools
that operate the fs (newfs_lfs, fsck_lfs, lfs_cleanerd)
lfs_kernel.h - stuff needed only in the kernel

and the following legacy headers that are expected to be mopped up and
folded into one of the above:
lfs_extern.h - function prototypes
ulfs_bswap.h - endian-independent support
ulfs_dinode.h - now contains very little
ulfs_dirhash.h - dirhash support
ulfs_extattr.h - extattr support
ulfs_extern.h - more function prototypes
ulfs_inode.h - assorted kernel-only declarations
ulfs_quota.h - quota support
ulfs_quota1.h - more quota support
ulfs_quota2.h - more quota support
ulfs_quotacommon.h - more quota support
ulfsmount.h - legacy copy of ufsmount material

branches: 1.117.2;
Prefix most of the cpp macros with lfs_ and LFS_ to avoid conflicts with ffs.
This was done so that boot blocks that want to compile both FFS and LFS in
the same file work.

Split lfs from ufs step 4:

Massedit all ufs symbols to be "ulfs" instead, to make sure there are
no conflicts with ufs. Confirmed with grep.

(This required changing a few comments that maybe should have been
left alone to say "ulfs", but we'll survive that.)

Split lfs from ufs step 3: rearrange config stuff.
Add new options:
LFS_EI
LFS_DIRHASH
LFS_EXTATTR
LFS_EXTATTR_AUTOSTART
LFS_QUOTA
LFS_QUOTA2

and update code referring to the corresponding FFS and UFS config
symbols to use the LFS versions. Disable the one extant reference
to APPLE_UFS in the ulfs files. Use opt_lfs.h only, not opt_ffs.h.

Split lfs from ufs, part 2:

Change all <ufs/ufs/foo.h> includes to <ufs/lfs/ulfs_foo.h>.

Stuff UFS_ in front of a few of ufs's symbols to reduce namespace
pollution. Specifically:
ROOTINO -> UFS_ROOTINO
WINO -> UFS_WINO
NXADDR -> UFS_NXADDR
NDADDR -> UFS_NDADDR
NIADDR -> UFS_NIADDR
MAXSYMLINKLEN -> UFS_MAXSYMLINKLEN
MAXSYMLINKLEN_UFS[12] -> UFS[12]_MAXSYMLINKLEN (for consistency)

Sort out ext2fs's misuse of NDADDR and NIADDR; fortunately, these have
the same values in ext2fs and ffs.

No functional change intended.

branches: 1.112.2;
Pass t_renamerace and t_rmdirrace tests.

Adapt dholland@'s fix to ufs_rename to fix PR kern/43582. Address several
other MP locking issues discovered during the course of investigating the
same problem.

Removed extraneous vn_lock() calls on the Ifile, since the Ifile writes
are controlled by the segment lock.

Fix PR kern/45982 by deemphasizing the estimate of how much metadata
will fill the empty space on disk when the disk is nearly empty
(t_renamerace crates a lot of inode blocks on a tiny empty disk).

branches: 1.111.2; 1.111.6; 1.111.8;
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: 1.110.6;
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.

branches: 1.109.2; 1.109.4;
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

Move declaration of ufs_hashlock into <ufs/ufs_extern.h> from each c source.

Remove clause 3 and 4 from TNF licenses

branches: 1.106.6; 1.106.8; 1.106.10;
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.

Merge vmlocking2 to head.

Fix a use of lfs_truncate() inside an #ifdef notyet (so no resulting change);
lfs_truncate() has lost its lwp argument.

branches: 1.103.4; 1.103.6; 1.103.8; 1.103.10;
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.

Merge ffs locking & brelse changes from the vmlocking branch.

branches: 1.101.6; 1.101.8; 1.101.10;
Move `struct dquot' and its supporting functions from quota.h to ufs_quota.c.

- Make quota-internal functions static.
- Clean up declarations in quota.h and ufs_extern.h. quota.h now has the
description of quota criterions, on-disk structure, user-kernel interface and
declaration of init/done functions. All ufs quota related function
prototypes go to ufs_extern.h.
- New functions ufsquota_init() and ufsquota_free() create or destroy the
quota fields of `struct inode'.
- chkdq() and chkiq() always update the quota fields of `struct inode' first.
- Only ufs_access() explicitely calls getinoquota().

No objections on tech-kern@

branches: 1.100.6; 1.100.8;
Replace some uses of lockmgr() / simplelocks.

__unused removal on arguments; approved by core.

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

branches: 1.97.2; 1.97.4;
Changes to help the roll-forward agent, to wit:

* Mark being-deleted files in the Ifile so we can finish deleting them
at fs mount time.
* Flag the Ifile with "cleaner must clean" when writers are waiting for
the cleaner, rather than relying solely on the cleaner's estimation of
whether it should clean or not.
* Note partial segments written by a user agent (in particular,
fsck_lfs) so that repeated rolls forward don't interfere with one
another.
* Add a new fcntl, LFCNPASS, that allows the log to wrap exactly once,
for better testing of the validity of checkpoints.
* Keep track of the on-disk nlink count when cleaning, so that we don't
partially complete directory operations while cleaning.
* Ensure that every single Ifile inode write represents a consistent
view of the filesystem. In particular, the accounting for the segment
we are writing the inode into must be correct, and the accounting for
the segment that inode used to reside in must be correct. Rather than
just rewriting the inode if we wrote it wrong, rewrite the necessary
ifile blocks before writing the inode so we never write it wrong.
* Don't unmark any VDIROP vnodes if we haven't written them to disk,
avoiding yet another problem with the "wait for the cleaner" error
return from lfs_putpages().

Also, move the last callback to an aiodone call, so we no longer do any
memory management from interrupt context.

Separate the (non-working) LFS kernel roll-forward code into its own file,
lfs_rfw.c.

Protect lfs_order_freelist() with the segment lock.

branches: 1.94.4;
integrate kauth.

Fixes to address the "vinvalbuf: dirty blocks" panic that can occur when
many inodes are cleaned at once. Make sure that we write all the pages
on vnodes that are being flushed, even if we don't think there's room;
drain v_numoutput before lfs_vflush() completes.

Also, don't allow a vnode that is in the process of being cleaned to be
chosen by getnewvnode(); this avoids a segment accounting panic in the case
that a large number of inodes are fed to lfs_markv() all at once.

Introduce another per-filesystem parameter, lfs_resvseg, to separate the
notion of "how many segments are reserved for the cleaner" from that of
"how many segments are not counted in lfs_bfree". The default value
used for existing filesystems is the same as the previous implicit value
of (lfs_minfreeseg / 2 + 1), modulo some sanity checking.

Count pending dirops on a per-filesystem basis, since once we start
writing them we can't stop until we're done. This seems to help stave off
the "no clean segments" panic in the case of filling the filesystem with
directories and small files (e.g. simultaneously unpacking more copies of
pkgsrc than will fit).

Add an explicit list initialization that was missing from my last commit.

Postpone the segment accounting changes coming from truncation until the
inode that makes those changes valid is either written to disk by
lfs_writeinode() or discarded by lfs_vfree().

A couple of locking fixes are also included as well.

Fix a fencepost error in the bitmap handling in extend_ifile(), and another
in lfs_freelist_prev().

Optimize the free list search a little more; in particular use words
instead of bytes for the index, and never search below fs->lfs_freehd.

Fix a bug in the previous version of the search (an erroneous assumption
that ino_t was signed).

Free the bitmap when we unmount the filesystem.

Keep the free list ordered. This solves a problem first pointed out to me
by Michel Oey, in which an aged LFS writes up to an extra Ifile block for
every file created; and paves the way for the truncation of the Ifile when
many files are deleted.

branches: 1.86.4; 1.86.6; 1.86.8; 1.86.10; 1.86.12;
merge ktrace-lwp.

merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.84.2;
64 bit inode changes.

branches: 1.83.2;
- sprinkle const
- avoid shadow variables.

Keep per-inode, per-fs, and subsystem-wide counts of blocks allocated through
lfs_balloc(), and use that to estimate the number of dirty pages belonging
to LFS (subsystem or filesystem). This is almost certainly wrong for
the case of a large mmap()ed region, but the accounting is tighter than
what we had before, and performs much better in the typical case of pages
dirtied through write().

Use splay trees, rather than a hash table, to manage the accounting of
blocks allocated through VOP_BALLOC() for pages to be written to disk.
This accounting no longer takes a noticeable fraction of the system CPU.

Consolidate the hash table we use to maintain the integrity of lfs_avail
into a single, system-wide table, rather than having a separate hash table
per inode. Significantly reduces the "system" cpu usage of your average
file write.

Keep track of the highest block held by an LFS inode, so that we can
be assured that the last byte of a file is always allocated. Previously
a file extension could cause the filesystem to be flushed, writing an
inconsistent inode to disk. Although this condition would be corrected
the next time blocks were written to disk, an intervening crash would leave
the filesystem in an inconsistent state, leaving fsck_lfs to complain
of an inode "partially truncated".

Protect various per-fs structures with fs->lfs_interlock simple_lock, to
improve behavior in the multiprocessor case. Add debugging segment-lock
assertion statements.

Make LFS dirops get their vnode first, before incrementing the dirop count,
to prevent a deadlock trying to call VOP_PUTPAGES() on a VDIROP vnode.
This can happen when a stacked filesystem is mounted on top of an LFS: an
LFS dirop needs to get a vnode, which is available from the upper layer.
The corresponding lower layer vnode, however, is VDIROP, so the upper layer
can't be cleaned out since its VOP_PUTPAGES() is passed through to the lower
layer, which waits for dirops to drain before it can proceed. Deadlock.

Tweak ufs_makeinode() and ufs_mkdir() to pass the a_vpp argument through
to VOP_VALLOC().

Partially addresses PR # 26043, though it probably does not completely fix
the problem described there.

branches: 1.76.2;
Straighten out the maze of ifdefs. Instead, consolidate all the debugging
stuff under '#ifdef DEBUG', and use sysctl knobs to turn on/off particular
parts of the debugging reporting (if DEBUG is enabled). Re-enable the LFS
statistics in sysctl, while I'm there. A bit of a rototill.

nuke trailing whitespace

Various minor LFS improvements:

* Note when lfs_putpages(9) thinks it is not going to be writing any
pages before calling genfs_putpages(9). This prevents a situation in
which blocks can be queued for writing without a segment header.
* Correct computation of NRESERVE(), though it is still a gross
overestimate in most cases. Note that if NRESERVE() is too high, it
may be impossible to create files on the filesystem. We catch this
case on filesystem mount and refuse to mount r/w.
* Allow filesystems to be mounted whose block size is == MAXBSIZE.
* Somewhere along the line, ufs_bmaparray(9) started mangling UNWRITTEN
entries in indirect blocks again, triggering a failed assertion "daddr
<= LFS_MAX_DADDR". Explicitly convert to and from int32_t to correct
this.
* Add a high-water mark for the number of dirty pages any given LFS can
hold before triggering a flush. This is settable by sysctl, but off
(zero) by default.
* Be more careful about the MAX_BYTES and MAX_BUFS computations so we
shouldn't see "please increase to at least zero" messages.
* Note that VBLK and VCHR vnodes can have nonzero values in di_db[0]
even though their v_size == 0. Don't panic when we see this.
* Change lfs_bfree to a signed quantity. The manner in which it is
processed before being passed to the cleaner means that sometimes it
may drop below zero, and the cleaner must be aware of this.
* Never report bfree < 0 (or higher than lfs_dsize) through
lfs_statvfs(9). This prevents df(1) from ever telling us that our full
filesystems have 16TB free.
* Account space allocated through lfs_balloc(9) that does not have
associated buffer headers, so that the pagedaemon doesn't run us out
of segments.
* Return ENOSPC from lfs_balloc(9) when bfree drops to zero.
* Address a deadlock in lfs_bmapv/lfs_markv when the filesystem is being
unmounted. Because vfs_busy() is a shared lock, and
lfs_bmapv/lfs_markv mark the filesystem vfs_busy(), the cleaner can be
holding the lock that umount() is blocking on, then try to vfs_busy()
again in getnewvnode().

branches: 1.73.4; 1.73.6;
Add a new flag, IN_MODIFY. This is like IN_UPDATE|IN_CHANGE, but unlike
setting those flags, it does not cause the inode to be written in the periodic
sync. This is used for writes to special files (devices and named pipes) and
FIFOs.

Do not preemptively sync updates to access times and modification times. They
are now updated in the inode only opportunistically, or when the file or device
is closed. (Really, it should be delayed beyond close, but this is enough to
help substantially with device nodes.)

And the most amusing part:
Trickle sync was broken on both FFS and ext2fs, in different ways. In FFS, the
periodic call to VFS_SYNC(MNT_LAZY) was still causing all file data to be
synced. In ext2fs, it was causing the metadata to *not* be synced. We now
only call VOP_UPDATE() on the node if we're doing MNT_LAZY. I've confirmed
that we do in fact trickle correctly now.

branches: 1.72.4;
cleanup IN_ADIROP/VDIROP handling a little.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22364, verified by myself.

- protect global resource counts with lfs_subsys_lock.
- clean up scattered externs a little.

branches: 1.69.2;
Back out the lwp/ktrace changes. They contained a lot of colateral damage,
and need to be examined and discussed more.

Undo part of the ktrace/lwp changes. In particular:
* Remove the "lwp *" argument that was added to vget(). Turns out
that nothing actually used it!
* Remove the "lwp *" arguments that were added to VFS_ROOT(), VFS_VGET(),
and VFS_FHTOVP(); all they did was pass it to vget() (which, as noted
above, didn't use it).
* Remove all of the "lwp *" arguments to internal functions that were added
just to appease the above.

Pass lwp pointers throughtout the kernel, as required, so that the lwpid can
be inserted into ktrace records. The general change has been to replace
"struct proc *" with "struct lwp *" in various function prototypes, pass
the lwp through and use l_proc to get the process pointer when needed.

Bump the kernel rev up to 1.6V

Add support for UFS2. UFS2 is an enhanced FFS, adding support for
64 bit block pointers, extended attribute storage, and a few
other things.

This commit does not yet include the code to manipulate the extended
storage (for e.g. ACLs), this will be done later.

Originally written by Kirk McKusick and Network Associates Laboratories for
FreeBSD.

Add simple_lock protection for lfs_seglock and lfs_subsys_pages; these will
be expanded to cover other per-fs and subsystem-wide data as well.

Fix a case of IN_MODIFIED being set without updating lfs_uinodes, resulting
in a "lfs_uinodes < 0" panic.

Fix a deadlock in lfs_putpages arising from the need to busy all pages in a
block; unbusy any that had already been busied before starting over.

Tabify, and fix some comment alignment problems.

Add code to UBCify LFS. This is still behind "#ifdef LFS_UBC" for now
(there are still some details to work out) but expect that to go
away soon. To support these basic changes (creation of lfs_putpages,
lfs_gop_write, mods to lfs_balloc) several other changes were made, to
wit:

* Create a writer daemon kernel thread whose purpose is to handle page
writes for the pagedaemon, but which also takes over some of the
functions of lfs_check(). This thread is started the first time an
LFS is mounted.

* Add a "flags" parameter to GOP_SIZE. Current values are
GOP_SIZE_READ, meaning that the call should return the size of the
in-core version of the file, and GOP_SIZE_WRITE, meaning that it
should return the on-disk size. One of GOP_SIZE_READ or
GOP_SIZE_WRITE must be specified.

* Instead of using malloc(...M_WAITOK) for everything, reserve enough
resources to get by and use malloc(...M_NOWAIT), using the reserves if
necessary. Use the pool subsystem for structures small enough that
this is feasible. This also obsoletes LFS_THROTTLE.

And a few that are not strictly necessary:

* Moves the LFS inode extensions off onto a separately allocated
structure; getting closer to LFS as an LKM. "Welcome to 1.6O."

* Unified GOP_ALLOC between FFS and LFS.

* Update LFS copyright headers to correct values.

* Actually cast to unsigned in lfs_shellsort, like the comment says.

* Keep track of which segments were empty before the previous
checkpoint; any segments that pass two checkpoints both dirty and
empty can be summarily cleaned. Do this. Right now lfs_segclean
still works, but this should be turned into an effectless
compatibility syscall.

make these compilable with lfs debug options.
(follow daddr_t change)

XXX maybe segment number should be 64bit.

Use PRId64 instead of hard coding "%lld" to fix build problems under
LP64 ports.

Fix printf() format strings problems caused by "daddr_t" change.

Bump daddr_t to 64 bits. Replace it with int32_t in all places where
it was used on-disk, so that on-disk formats remain the same.
Remove ufs_daddr_t and ufs_lbn_t for the time being.

use lfs_unmark_vnode instead of duplicated code fragments.

make sure i_lfs_fragsize is initialized.
fix panic "lfs_writefile: more than one fragment!"
PR 18974.

Phase one of my three-phase plan to make LFS play nice with UBC, and bug-fixes
I found while making sure there weren't any new ones.

* Make the write clusters keep track of the buffers whose blocks they contain.
This should make it possible to (1) write clusters using a page mapping
instead of malloc, if desired, and (2) schedule blocks for rewriting
(somewhere else) if a write error occurs. Code is present to use
pagemove() to construct the clusters but that is untested and will go away
anyway in favor of page mapping.
* DEBUG now keeps a log of Ifile writes, so that any lingering instances of
the "dirty bufs" problem can be properly debugged.
* Keep track of whether the Ifile has been dirtied by various routines that
can be called by lfs_segwrite, and loop on that until it is clean, for
a checkpoint. Checkpoints need to be squeaky clean.
* Warn the user (once) if the Ifile grows larger than is reasonable for their
buffer cache. Both lfs_mountfs and lfs_unmount check since the Ifile can
grow.
* If an inode is not found in a disk block, try rereading the block, under
the assumption that the block was copied to a cluster and then freed.
* Protect WRITEINPROG() with splbio() to fix a hang in lfs_update.

Correct free list tail pointer, when adding blocks of new inodes to v2
filesystems. Should fix PR #14408.

use the new compatibility routines to allow mmap() to work
(in the same non-coherent fashion that it worked pre-UBC)
until someone has time to do it the right way.

add spaces for KNF. confirmed to produce identical objects.

add RCSID

branches: 1.51.2;
initialize the vnode's copy of the size in lfs_ialloc().

don't depend on other headers to include sys/proc.h for us.

a whole bunch of changes to improve performance and robustness under load:

- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.

The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.

branches: 1.48.2;
Merge the short-lived perseant-lfsv2 branch into the trunk.

Kernels and tools understand both v1 and v2 filesystems; newfs_lfs
generates v2 by default. Changes for the v2 layout include:

- Segments of non-PO2 size and arbitrary block offset, so these can be
matched to convenient physical characteristics of the partition (e.g.,
stripe or track size and offset).

- Address by fragment instead of by disk sector, paving the way for
non-512-byte-sector devices. In theory fragments can be as large
as you like, though in reality they must be smaller than MAXBSIZE in size.

- Use serial number and filesystem identifier to ensure that roll-forward
doesn't get old data and think it's new. Roll-forward is enabled for
v2 filesystems, though not for v1 filesystems by default.

- The inode free list is now a tailq, paving the way for undelete (undelete
is not yet implemented, but can be without further non-backwards-compatible
changes to disk structures).

- Inode atime information is kept in the Ifile, instead of on the inode;
that is, the inode is never written *just* because atime was changed.
Because of this the inodes remain near the file data on the disk, rather
than wandering all over as the disk is read repeatedly. This speeds up
repeated reads by a small but noticeable amount.

Other changes of note include:

- The ifile written by newfs_lfs can now be of arbitrary length, it is no
longer restricted to a single indirect block.

- Fixed an old bug where ctime was changed every time a vnode was created.
I need to look more closely to make sure that the times are only updated
during write(2) and friends, not after-the-fact during a segment write,
and certainly not by the cleaner.

branches: 1.47.2; 1.47.4;
use _KERNEL_OPT

branches: 1.46.2;
Get rid of some old unnecessary code that cleared B_NEEDCOMMIT from buffers in
lfs_writeseg (possibly after they had been freed).

If MALLOCLOG is defined, make lfs_newbuf and lfs_freebuf pass along the
caller's file and line to _malloc and _free.

Initial integration of the Unified Buffer Cache project.

If LFS_DO_ROLLFORWARD is defined, roll forward from the older checkpoint
on mount, through the newer checkpoint and on through any newer
partial-segments that may have been written but not checkpointed because
of an intervening crash.

LFS_DO_ROLLFORWARD is not defined by default.

Various bug-fixes to LFS, to wit:


Kernel:

* Add runtime quantity lfs_ravail, the number of disk-blocks reserved
for writing. Writes to the filesystem first reserve a maximum amount
of blocks before their write is allowed to proceed; after the blocks
are allocated the reserved total is reduced by a corresponding amount.

If the lfs_reserve function cannot immediately reserve the requested
number of blocks, the inode is unlocked, and the thread sleeps until
the cleaner has made enough space available for the blocks to be
reserved. In this way large files can be written to the filesystem
(or, smaller files can be written to a nearly-full but thoroughly
clean filesystem) and the cleaner can still function properly.

* Remove explicit switching on dlfs_minfreeseg from the kernel code; it
is now merely a fs-creation parameter used to compute dlfs_avail and
dlfs_bfree (and used by fsck_lfs(8) to check their accuracy). Its
former role is better assumed by a properly computed dlfs_avail.

* Bounds-check inode numbers submitted through lfs_bmapv and lfs_markv.
This prevents a panic, but, if the cleaner is feeding the filesystem
the wrong data, you are still in a world of hurt.

* Cleanup: remove explicit references of DEV_BSIZE in favor of
btodb()/dbtob().

lfs_cleanerd:

* Make -n mean "send N segments' blocks through a single call to
lfs_markv". Previously it had meant "clean N segments though N calls
to lfs_markv, before looking again to see if more need to be cleaned".
The new behavior gives better packing of direct data on disk with as
little metadata as possible, largely alleviating the problem that the
cleaner can consume more disk through inefficient use of metadata than
it frees by moving dirty data away from clean "holes" to produce
entirely clean segments.

* Make -b mean "read as many segments as necessary to write N segments
of dirty data back to disk", rather than its former meaning of "read
as many segments as necessary to free N segments worth of space". The
new meaning, combined with the new -n behavior described above,
further aids in cleaning storage efficiency as entire segments can be
written at once, using as few blocks as possible for segment summaries
and inode blocks.

* Make the cleaner take note of segments which could not be cleaned due
to error, and not attempt to clean them until they are entirely free
of dirty blocks. This prevents the case in which a cleanerd running
with -n 1 and without -b (formerly the default) would spin trying
repeatedly to clean a corrupt segment, while the remaining space
filled and deadlocked the filesystem.

* Update the lfs_cleanerd manual page to describe all the options,
including the changes mentioned here (in particular, the -b and -n
flags were previously undocumented).

fsck_lfs:

* Check, and optionally fix, lfs_avail (to an exact figure) and
lfs_bfree (within a margin of error) in pass 5.

newfs_lfs:

* Reduce the default dlfs_minfreeseg to 1/20 of the total segments.

* Add a warning if the sgs disklabel field is 16 (the default for FFS'
cpg, but not usually desirable for LFS' sgs: 5--8 is a better range).

* Change the calculation of lfs_avail and lfs_bfree, corresponding to
the kernel changes mentioned above.

mount_lfs:

* Add -N and -b options to pass corresponding -n and -b options to
lfs_cleanerd.

* Default to calling lfs_cleanerd with "-b -n 4".


[All of these changes were largely tested in the 1.5 branch, with the
idea that they (along with previous un-pulled-up work) could be applied
to the branch while it was still in ALPHA2; however my test system has
experienced corruption on another filesystem (/dev/console has gone
missing :^), and, while I believe this unrelated to the LFS changes, I
cannot with good conscience request that the changes be pulled up.]

Clean up accounting of lfs_uinodes (dirty but unwritten inodes).

Make lfs_uinodes a signed quantity for debugging purposes, and set it to
zero as fs mount time.

Enclose setting/clearing of the dirty flags (IN_MODIFIED, IN_ACCESSED,
IN_CLEANING) in macros, and use those macros everywhere. Make
LFS_ITIMES use these macros; updated the ITIMES macro in inode.h to know
about this. Make ufs_getattr use ITIMES instead of FFS_ITIMES.

i_lfs_effnblks fixes. Put debugging printfs under #ifdef DEBUG_LFS.

Rearrange code around getnewvnode as was already done for ffs, to avoid
locking against oneself because getnewvnode recycles a softdep-using vnode.

remove include of <vm/vm.h> and <uvm/uvm_extern.h>

Fixes associated with filling an LFS:

Change the space computation to appear to change the size of the *disk*
rather than the *bytes used* when more segment summaries and inode
blocks are written. Try to estimate the amount of space that these will
take up when more files are written, so the disk size doesn't change too
much.

Regularize error returns from lfs_valloc, lfs_balloc, lfs_truncate: they
now fail entirely, rather than succeeding half-way and leaving the fs in
an inconsistent state.

Rewrite lfs_truncate, mostly stealing from ffs_truncate. The old
lfs_truncate had difficulty truncating a large file to a non-zero size
(indirect blocks were not handled appropriately).

Unmark VDIROP on fvp after ufs_remove, ufs_rmdir, so these can be
reclaimed immediately: this vnode would not be written to disk again
anyway if the removal succeeded, and if it failed, no directory
operation occurred.

ufs_makeinode and ufs_mkdir now remove IN_ADIROP on error.

fix my own typo, grr....

Read i_ffs_gen from the version number in the Ifile during lfs_valloc,
instead of keeping it always == 1. (The ifile version number is
increased on vfree.) May address PR #7213, but I haven't been able to
test thoroughly enough to say for sure.

Update lfs_vunref for the fact that now a vnode can be locked with no
references (locked for VOP_INACTIVE at the end of vrele) and it's okay.
Check the return value of lfs_vref where appropriate.
Fixes PR #s 10285 and 10352.

branches: 1.34.2;
Protect inode free list with seglock, instead of separate lock, so that
the head of the inode free list (on the superblock) always matches the
rest of the free list (in the ifile).

Protect lfs_fragextend with seglock, to prevent the segment byte count
fudging from making its way to disk.

Don't try to inactivate dirop vnodes that are still in the middle of
their dirop (may address PR#10285).

update for IN_ACCESSED changes

branches: 1.32.2;
Prevent dirops from getting around lfs_check and wedging the buffer cache.
All the dirop vnops now mark the inodes with a new flag, IN_ADIROP, which
is removed as soon as the dirop is done (as opposed to VDIROP which stays
until the file is written). To address one issue raised in PR#9357.

Changes to stabilize LFS. The first two of these should also apply to the
1.4 branch.

* Use a separate per-fs lock, instead of ufs_hashlock, to protect the Inode
free list. This seems to prevent the "lockmgr: %d, not exclusive lock holder
%d, unlocking" message I was mis-attributing last night to an unlocked vnode
being passed to vrele.

* Change calling semantics of lfs_ifind, to give better error reporting:
If fed a struct buf, it can report the block number of the offending inode
block as well as the inode number.

* Back out rev 1.10 of lfs_subr.c, since the replacement code was slightly
uglier while being functionally identical.

* Make lfs_vunref use the same free list convention as vrele/vput, so that
vget does not remove vnodes from a hash list they are not on.

Fix error returns on lfs vnops so that locks and reference counts are
preserved. Handle dirop accounting in lfs_vfree for this case as well.
May address PR#8823.

Add Kirk McKusick's soft updates code to the trunk. Not enabled by
default, as the copyright on the main file (ffs_softdep.c) is such
that is has been put into gnusrc. options SOFTDEP will pull this
in. This code also contains the trickle syncer.

Bump version number to 1.4O

Back out my patch of the 8th (to address unreferenced inode problem).
Apparently this needs more thought.

If ifile blocks were written before dirops were complete, and then the
system crashed, inodes could be allocated that were not referenced. (Though
not a serious problem, it evidences itself in phase 4 of fsck_lfs.) Fix
this by marking if_daddr with UNASSIGNED before the inodes are actually
written; at mount time the ifile is checked for UNASSIGNED entries and
any that are found are linked back into the free list. (The latter
functionality should move into the roll-forward agent when it materializes.)

branches: 1.26.2;
Address ufs_hashlock/ufs_ihashins protocol bug, discovered while doing a
post-mortem of a production machine. Also, take the active dirop
count off of the fs and make it global (since it is measuring a global
resource) and tie the threshold value LFS_MAXDIROP to desiredvnodes.

branches: 1.25.2; 1.25.4; 1.25.6;
Make changes that will allow an LFS filesystem to be used as the root
filesystem. In particular,

- Fix mknod deadlock, described in PR 8172.
- Enable lfs_mountroot.
- Make lfs_writevnodes treat filesystems mounted on lfs device nodes properly,
by flushing that device rather than trying to add blocks to the device inode.

This, in combination with lfs boot blocks, will allow operation of an all-lfs
system.

Modify file systems to deal with struct lock in struct vnode. All leaf
fs's other than nfs use genfs_lock() for locking.

Modify lookup routines to set PDIRUNLOCK when they unlock the parrent.

squash some compiler warnings on debug printfs by casting to int

Minor changes to the segment live bytes calculation. In particular, fixed
a bug in fragment extension that could run the count negative. Also, don't
overcount for inodes, and don't count segment summaries. Thus, for empty
segments the live bytes count should now be exactly zero.

Other half of the ufs_hashlock locking fix (oops)

Fix locking panic on ufs_hashlock

Take out the `#ifdef USE_UFSHASH'; use ufs_hashlock to lock the inode free
list instead of free_lock.

branches: 1.18.2;
completely remove Mach VM support. all that is left is the all the
header files as UVM still uses (most of) these.

New sources should leave the LFS in a more-or-less working state. Changes
include:

- DIROP segregation is enabled, and greater care is taken
to make sure that a checkpoint completes. Fsck is not
needed to remount the filesystem.
- Several checks to make sure that the LFS subsystem does not
overuse various resources (memory, in particular).
- The cleaner routines, lfs_markv in particular, are completely
rewritten. A buffer overflow is removed. Greater care is taken
to ensure that inodes come from where lfs_cleanerd say they come
from (so we know nothing has changed since lfs_bmapv was called).
- Fragment allocation is fixed, so that writes beyond end-of-file
do the right thing.

Use DINODE_SIZE rather than sizeof(struct dinode).

Use the pool allocator and the "nointr" pool page allocator for LFS inodes.

Always include fifos; "not an option any more".

Protect various config(8)-generated files from inclusion while
building LKMs. Fixes PR 5557.

Use the newly-defined opt_quota.h.

Merge with Lite2 + local changes

add UVM stuff.

Don't cast 64bit (off_t) file sizes to vm_offset_t (32bit on many
architectures), truncate them intelligently instead.
The truncation is done centralized in vnode_pager.c.
This prevents from wrap-over effects when parts of large (>2^32 byte) files
are mmapped.
Don't allow to mmap above the numerical range of vm_offset_t.
This is considered a temporary solution until the vm system handles the
object sizes/offsets more cleanly.

Add support for ext2fs, this needed a few modifications to ufs/ufs/inode.h:
- added an "union inode_ext" to struct inode, for the per-fs extentions.
For now only ext2fs uses it.
- i_din is now an union:
union {
struct dinode ffs_din; /* 128 bytes of the on-disk dinode. */
struct ext2fs_dinode e2fs_din; /* 128 bytes of the on-disk dinode. */
} i_din
Added a lot of #define i_ffs_* and i_e2fs_* to access the fields.
- Added two macros: FFS_ITIMES and EXT2FS_ITIMES. ITIMES calls the rigth
macro, depending on the time of the inode. ITIMES is used where necessary,
FFS_ITIMES and EXT2FS_ITIMES in other places.

Just increment the generation count. Using the time is bogus and defeats
fsirand(8).

branches: 1.6.6;
revert previous kprintf changes

printf -> kprintf, sprintf -> ksprintf

Appease gcc: unused variables if !QUOTA

lfs prototypes

New RCS ID's, take two. they're more aesthecially pleasant, and use 'NetBSD'

branches: 1.1.1;
Update to 4.4-Lite fs code, with local changes.

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: 1.137.10;
Consistently use {,UN}MARK_VNODE macros rather than function calls.

Rename i_flag to i_state.

The similarity to i_flags has previously caused errors.

branches: 1.135.6;
Fill in some XXXs with the exact action described in them. match
lfs_valloc behaviour.

#if DIAGNOSTIC panic ---> KASSERT

Replace some #if DEBUG by this too. DEBUG is only for expensive
assertions; these are not.

branches: 1.133.2;
Remove unused <sys/tree.h>

Comments

branches: 1.131.2;
Fix minor bitrot in #if 0 or otherwise disabled code.

Fix wrong code in lfs_valloc_fixed(). It was overwriting the inode
number it was supposed to be allocating with the head of the inode
freelist, then applying the wrong test to that result. Net result:
unless the freelist was empty (in which case it would always fail),
it would in general drop a bunch of entries from the freelist.

This code seems to have been broken when the first version of lfsv2
was imported onto the perseant-lfsv2 branch in -r1.47.2.1, and
remained broken since, in spite of having been moved to lfs_rfw.c and
back and rearranged quite a bit in the meantime.

Sigh.

Found by Coverity in a rather confusing way as CID 1316545.

Use the lfs dinode accessors in place of the ufs-derived ones.
(Mostly.)

The ufs-derived ones are fake structure member macros, which are gross
and not very safe. Also, it seems that a lot of places in the lfs code
were using the ffsv1 branch of them unconditionally, and this way it's
guaranteed all those places have been updated.

Found while doing this: for non-devices, have getattr produce NODEV
in the rdev field instead of leaking the address of the first direct
block.

Fix IFILE pointer calculation when scanning freelist.

Hack up dinode usage to be 64 vs. 32 as needed. Part 1.

(This part changes the native lfs code; the ufs-derived code already
has 64 vs. 32 logic, but as aspects of it are unsafe, and don't
entirely interoperate cleanly with the lfs 64/32 stuff, pass 2 will be
rehashing that.)

Add IFILE32 and IFILE64 structures for the on-disk ifile entries.
Add and use accessors. There are also a bunch of places that cast and
I hope I've found them all...

Use accessor functions for the version field of the lfs superblock.
I thought at first maybe the cases that test the version should be
rolled into the accessors, but on the whole I think the conclusion on
that is no.

Add a new lfs header file: lfs_accessors.h.

This contains all the accessor functions and macros out of lfs.h.
Add an include of lfs_accessors.h after all uses of lfs.h... except
for code that wants to define its own struct lfs-alike that the
accessors are supposed to play along with. For these, set STRUCT_LFS
and include lfs_accessors.h after the necessary structure has been
defined, so that lfs_accessors.h can emit functions in terms of it.

More lfs superblock accessors.
(This changes the rest of the code over; all the accessors were
already added.)

The difference between this commit and the previous one is arbitrary,
but the previous one passed the regression tests on its own so I'm
keeping it separate to help with any bisections that might be needed
in the future.

Switch to accessor functions for elements of the LFS on-disk
superblock. This will allow switching between 32/64 bit forms on the
fly; it will also allow handling LFS_EI reasonably tidily. (That
currently doesn't work on the superblock.)

It also gets rid of cpp abuse in the form of fake structure member
macros.

Also, instead of doing sleep/wakeup on &lfs_avail and &lfs_nextseg
inside the on-disk superblock, add extra elements to the in-memory
struct lfs for this. (XXX: these should be changed to condvars, but
not right now)

XXX: this migrates a structure needed by the lfs code in libsa (struct
salfs) into lfs.h, where it doesn't belong, but for the time being
this is necessary in order to allow the accessors (and the various
lfs macros and other goop that relies on them) to compile.

Don't cast the return value of malloc.

Change lfs from hash table to vcache.

- Change lfs_valloc() to return an inode number and version instead of
a vnode and move lfs_ialloc() and lfs_vcreate() to new lfs_init_vnode().

- Add lfs_valloc_fixed() to allocate a known inode, used by kernel
roll forward.

- Remove lfs_*ref(), these functions cannot coexist with vcache and
their commented behaviour is far away from their implementation.

- Add the cleaner lwp and blockinfo to struct ulfsmount so lfs_loadvnode()
may use hints from the cleaner.

- Remove vnode locks from ulfs_lookup() like we did with ufs_lookup().

branches: 1.119.6;
Add more of the bits for supporting quotas.

Add lfs_kernel.h for declarations that don't need to be exposed to userland.

lfs currently has the following headers:
lfs.h - on-disk structures and stuff needed for userlevel tools
lfs_inode.h - additional restricted materials for userlevel tools
that operate the fs (newfs_lfs, fsck_lfs, lfs_cleanerd)
lfs_kernel.h - stuff needed only in the kernel

and the following legacy headers that are expected to be mopped up and
folded into one of the above:
lfs_extern.h - function prototypes
ulfs_bswap.h - endian-independent support
ulfs_dinode.h - now contains very little
ulfs_dirhash.h - dirhash support
ulfs_extattr.h - extattr support
ulfs_extern.h - more function prototypes
ulfs_inode.h - assorted kernel-only declarations
ulfs_quota.h - quota support
ulfs_quota1.h - more quota support
ulfs_quota2.h - more quota support
ulfs_quotacommon.h - more quota support
ulfsmount.h - legacy copy of ufsmount material

branches: 1.117.2;
Prefix most of the cpp macros with lfs_ and LFS_ to avoid conflicts with ffs.
This was done so that boot blocks that want to compile both FFS and LFS in
the same file work.

Split lfs from ufs step 4:

Massedit all ufs symbols to be "ulfs" instead, to make sure there are
no conflicts with ufs. Confirmed with grep.

(This required changing a few comments that maybe should have been
left alone to say "ulfs", but we'll survive that.)

Split lfs from ufs step 3: rearrange config stuff.
Add new options:
LFS_EI
LFS_DIRHASH
LFS_EXTATTR
LFS_EXTATTR_AUTOSTART
LFS_QUOTA
LFS_QUOTA2

and update code referring to the corresponding FFS and UFS config
symbols to use the LFS versions. Disable the one extant reference
to APPLE_UFS in the ulfs files. Use opt_lfs.h only, not opt_ffs.h.

Split lfs from ufs, part 2:

Change all <ufs/ufs/foo.h> includes to <ufs/lfs/ulfs_foo.h>.

Stuff UFS_ in front of a few of ufs's symbols to reduce namespace
pollution. Specifically:
ROOTINO -> UFS_ROOTINO
WINO -> UFS_WINO
NXADDR -> UFS_NXADDR
NDADDR -> UFS_NDADDR
NIADDR -> UFS_NIADDR
MAXSYMLINKLEN -> UFS_MAXSYMLINKLEN
MAXSYMLINKLEN_UFS[12] -> UFS[12]_MAXSYMLINKLEN (for consistency)

Sort out ext2fs's misuse of NDADDR and NIADDR; fortunately, these have
the same values in ext2fs and ffs.

No functional change intended.

branches: 1.112.2;
Pass t_renamerace and t_rmdirrace tests.

Adapt dholland@'s fix to ufs_rename to fix PR kern/43582. Address several
other MP locking issues discovered during the course of investigating the
same problem.

Removed extraneous vn_lock() calls on the Ifile, since the Ifile writes
are controlled by the segment lock.

Fix PR kern/45982 by deemphasizing the estimate of how much metadata
will fill the empty space on disk when the disk is nearly empty
(t_renamerace crates a lot of inode blocks on a tiny empty disk).

branches: 1.111.2; 1.111.6; 1.111.8;
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: 1.110.6;
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.

branches: 1.109.2; 1.109.4;
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

Move declaration of ufs_hashlock into <ufs/ufs_extern.h> from each c source.

Remove clause 3 and 4 from TNF licenses

branches: 1.106.6; 1.106.8; 1.106.10;
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.

Merge vmlocking2 to head.

Fix a use of lfs_truncate() inside an #ifdef notyet (so no resulting change);
lfs_truncate() has lost its lwp argument.

branches: 1.103.4; 1.103.6; 1.103.8; 1.103.10;
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.

Merge ffs locking & brelse changes from the vmlocking branch.

branches: 1.101.6; 1.101.8; 1.101.10;
Move `struct dquot' and its supporting functions from quota.h to ufs_quota.c.

- Make quota-internal functions static.
- Clean up declarations in quota.h and ufs_extern.h. quota.h now has the
description of quota criterions, on-disk structure, user-kernel interface and
declaration of init/done functions. All ufs quota related function
prototypes go to ufs_extern.h.
- New functions ufsquota_init() and ufsquota_free() create or destroy the
quota fields of `struct inode'.
- chkdq() and chkiq() always update the quota fields of `struct inode' first.
- Only ufs_access() explicitely calls getinoquota().

No objections on tech-kern@

branches: 1.100.6; 1.100.8;
Replace some uses of lockmgr() / simplelocks.

__unused removal on arguments; approved by core.

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

branches: 1.97.2; 1.97.4;
Changes to help the roll-forward agent, to wit:

* Mark being-deleted files in the Ifile so we can finish deleting them
at fs mount time.
* Flag the Ifile with "cleaner must clean" when writers are waiting for
the cleaner, rather than relying solely on the cleaner's estimation of
whether it should clean or not.
* Note partial segments written by a user agent (in particular,
fsck_lfs) so that repeated rolls forward don't interfere with one
another.
* Add a new fcntl, LFCNPASS, that allows the log to wrap exactly once,
for better testing of the validity of checkpoints.
* Keep track of the on-disk nlink count when cleaning, so that we don't
partially complete directory operations while cleaning.
* Ensure that every single Ifile inode write represents a consistent
view of the filesystem. In particular, the accounting for the segment
we are writing the inode into must be correct, and the accounting for
the segment that inode used to reside in must be correct. Rather than
just rewriting the inode if we wrote it wrong, rewrite the necessary
ifile blocks before writing the inode so we never write it wrong.
* Don't unmark any VDIROP vnodes if we haven't written them to disk,
avoiding yet another problem with the "wait for the cleaner" error
return from lfs_putpages().

Also, move the last callback to an aiodone call, so we no longer do any
memory management from interrupt context.

Separate the (non-working) LFS kernel roll-forward code into its own file,
lfs_rfw.c.

Protect lfs_order_freelist() with the segment lock.

branches: 1.94.4;
integrate kauth.

Fixes to address the "vinvalbuf: dirty blocks" panic that can occur when
many inodes are cleaned at once. Make sure that we write all the pages
on vnodes that are being flushed, even if we don't think there's room;
drain v_numoutput before lfs_vflush() completes.

Also, don't allow a vnode that is in the process of being cleaned to be
chosen by getnewvnode(); this avoids a segment accounting panic in the case
that a large number of inodes are fed to lfs_markv() all at once.

Introduce another per-filesystem parameter, lfs_resvseg, to separate the
notion of "how many segments are reserved for the cleaner" from that of
"how many segments are not counted in lfs_bfree". The default value
used for existing filesystems is the same as the previous implicit value
of (lfs_minfreeseg / 2 + 1), modulo some sanity checking.

Count pending dirops on a per-filesystem basis, since once we start
writing them we can't stop until we're done. This seems to help stave off
the "no clean segments" panic in the case of filling the filesystem with
directories and small files (e.g. simultaneously unpacking more copies of
pkgsrc than will fit).

Add an explicit list initialization that was missing from my last commit.

Postpone the segment accounting changes coming from truncation until the
inode that makes those changes valid is either written to disk by
lfs_writeinode() or discarded by lfs_vfree().

A couple of locking fixes are also included as well.

Fix a fencepost error in the bitmap handling in extend_ifile(), and another
in lfs_freelist_prev().

Optimize the free list search a little more; in particular use words
instead of bytes for the index, and never search below fs->lfs_freehd.

Fix a bug in the previous version of the search (an erroneous assumption
that ino_t was signed).

Free the bitmap when we unmount the filesystem.

Keep the free list ordered. This solves a problem first pointed out to me
by Michel Oey, in which an aged LFS writes up to an extra Ifile block for
every file created; and paves the way for the truncation of the Ifile when
many files are deleted.

branches: 1.86.4; 1.86.6; 1.86.8; 1.86.10; 1.86.12;
merge ktrace-lwp.

merge yamt-vop branch. remove following VOPs.

VOP_BLKATOFF
VOP_VALLOC
VOP_BALLOC
VOP_REALLOCBLKS
VOP_VFREE
VOP_TRUNCATE
VOP_UPDATE

branches: 1.84.2;
64 bit inode changes.

branches: 1.83.2;
- sprinkle const
- avoid shadow variables.

Keep per-inode, per-fs, and subsystem-wide counts of blocks allocated through
lfs_balloc(), and use that to estimate the number of dirty pages belonging
to LFS (subsystem or filesystem). This is almost certainly wrong for
the case of a large mmap()ed region, but the accounting is tighter than
what we had before, and performs much better in the typical case of pages
dirtied through write().

Use splay trees, rather than a hash table, to manage the accounting of
blocks allocated through VOP_BALLOC() for pages to be written to disk.
This accounting no longer takes a noticeable fraction of the system CPU.

Consolidate the hash table we use to maintain the integrity of lfs_avail
into a single, system-wide table, rather than having a separate hash table
per inode. Significantly reduces the "system" cpu usage of your average
file write.

Keep track of the highest block held by an LFS inode, so that we can
be assured that the last byte of a file is always allocated. Previously
a file extension could cause the filesystem to be flushed, writing an
inconsistent inode to disk. Although this condition would be corrected
the next time blocks were written to disk, an intervening crash would leave
the filesystem in an inconsistent state, leaving fsck_lfs to complain
of an inode "partially truncated".

Protect various per-fs structures with fs->lfs_interlock simple_lock, to
improve behavior in the multiprocessor case. Add debugging segment-lock
assertion statements.

Make LFS dirops get their vnode first, before incrementing the dirop count,
to prevent a deadlock trying to call VOP_PUTPAGES() on a VDIROP vnode.
This can happen when a stacked filesystem is mounted on top of an LFS: an
LFS dirop needs to get a vnode, which is available from the upper layer.
The corresponding lower layer vnode, however, is VDIROP, so the upper layer
can't be cleaned out since its VOP_PUTPAGES() is passed through to the lower
layer, which waits for dirops to drain before it can proceed. Deadlock.

Tweak ufs_makeinode() and ufs_mkdir() to pass the a_vpp argument through
to VOP_VALLOC().

Partially addresses PR # 26043, though it probably does not completely fix
the problem described there.

branches: 1.76.2;
Straighten out the maze of ifdefs. Instead, consolidate all the debugging
stuff under '#ifdef DEBUG', and use sysctl knobs to turn on/off particular
parts of the debugging reporting (if DEBUG is enabled). Re-enable the LFS
statistics in sysctl, while I'm there. A bit of a rototill.

nuke trailing whitespace

Various minor LFS improvements:

* Note when lfs_putpages(9) thinks it is not going to be writing any
pages before calling genfs_putpages(9). This prevents a situation in
which blocks can be queued for writing without a segment header.
* Correct computation of NRESERVE(), though it is still a gross
overestimate in most cases. Note that if NRESERVE() is too high, it
may be impossible to create files on the filesystem. We catch this
case on filesystem mount and refuse to mount r/w.
* Allow filesystems to be mounted whose block size is == MAXBSIZE.
* Somewhere along the line, ufs_bmaparray(9) started mangling UNWRITTEN
entries in indirect blocks again, triggering a failed assertion "daddr
<= LFS_MAX_DADDR". Explicitly convert to and from int32_t to correct
this.
* Add a high-water mark for the number of dirty pages any given LFS can
hold before triggering a flush. This is settable by sysctl, but off
(zero) by default.
* Be more careful about the MAX_BYTES and MAX_BUFS computations so we
shouldn't see "please increase to at least zero" messages.
* Note that VBLK and VCHR vnodes can have nonzero values in di_db[0]
even though their v_size == 0. Don't panic when we see this.
* Change lfs_bfree to a signed quantity. The manner in which it is
processed before being passed to the cleaner means that sometimes it
may drop below zero, and the cleaner must be aware of this.
* Never report bfree < 0 (or higher than lfs_dsize) through
lfs_statvfs(9). This prevents df(1) from ever telling us that our full
filesystems have 16TB free.
* Account space allocated through lfs_balloc(9) that does not have
associated buffer headers, so that the pagedaemon doesn't run us out
of segments.
* Return ENOSPC from lfs_balloc(9) when bfree drops to zero.
* Address a deadlock in lfs_bmapv/lfs_markv when the filesystem is being
unmounted. Because vfs_busy() is a shared lock, and
lfs_bmapv/lfs_markv mark the filesystem vfs_busy(), the cleaner can be
holding the lock that umount() is blocking on, then try to vfs_busy()
again in getnewvnode().

branches: 1.73.4; 1.73.6;
Add a new flag, IN_MODIFY. This is like IN_UPDATE|IN_CHANGE, but unlike
setting those flags, it does not cause the inode to be written in the periodic
sync. This is used for writes to special files (devices and named pipes) and
FIFOs.

Do not preemptively sync updates to access times and modification times. They
are now updated in the inode only opportunistically, or when the file or device
is closed. (Really, it should be delayed beyond close, but this is enough to
help substantially with device nodes.)

And the most amusing part:
Trickle sync was broken on both FFS and ext2fs, in different ways. In FFS, the
periodic call to VFS_SYNC(MNT_LAZY) was still causing all file data to be
synced. In ext2fs, it was causing the metadata to *not* be synced. We now
only call VOP_UPDATE() on the node if we're doing MNT_LAZY. I've confirmed
that we do in fact trickle correctly now.

branches: 1.72.4;
cleanup IN_ADIROP/VDIROP handling a little.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22364, verified by myself.

- protect global resource counts with lfs_subsys_lock.
- clean up scattered externs a little.

branches: 1.69.2;
Back out the lwp/ktrace changes. They contained a lot of colateral damage,
and need to be examined and discussed more.

Undo part of the ktrace/lwp changes. In particular:
* Remove the "lwp *" argument that was added to vget(). Turns out
that nothing actually used it!
* Remove the "lwp *" arguments that were added to VFS_ROOT(), VFS_VGET(),
and VFS_FHTOVP(); all they did was pass it to vget() (which, as noted
above, didn't use it).
* Remove all of the "lwp *" arguments to internal functions that were added
just to appease the above.

Pass lwp pointers throughtout the kernel, as required, so that the lwpid can
be inserted into ktrace records. The general change has been to replace
"struct proc *" with "struct lwp *" in various function prototypes, pass
the lwp through and use l_proc to get the process pointer when needed.

Bump the kernel rev up to 1.6V

Add support for UFS2. UFS2 is an enhanced FFS, adding support for
64 bit block pointers, extended attribute storage, and a few
other things.

This commit does not yet include the code to manipulate the extended
storage (for e.g. ACLs), this will be done later.

Originally written by Kirk McKusick and Network Associates Laboratories for
FreeBSD.