sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

Handle UFS/FFS file deletion from cylinder groups with check-hash failure.

When a file is deleted, its blocks need to be put back in the free
block list and its inode needs to be put back in the inode free list.
These lists reside in cylinder-group maps. If either some of its blocks
or its inode reside in a cylinder-group map with a bad check hash
it is not possible to free the associated resource. Since the cylinder
group cannot be repaired until the filesystem is unmounted these
resources cannot be freed. They simply accumulate in memory. And
any attempt to unmount the filesystem loops forever trying to flush them.

With this change, the resource update claims to succeed so that the
file deletion can successfully complete. The filesystem is marked as
requiring an fsck so that before the next time that the filesystem is
mounted, the offending cylinder groups are reconstructed causing the
lost resources to be reclaimed.

A better solution would be to downgrade the filesystem to read-only,
but that capability is not currently implemented.

Reported-by: Peter Holm
Tested-by: Peter Holm
MFC-after: 1 week
Sponsored-by: The FreeBSD Foundation

UFS/FFS: Migrate to modern uintXX_t from u_intXX_t.

As per https://lists.freebsd.org/archives/freebsd-scsi/2023-July/000257.html
move to the modern uintXX_t. While here also migrate u_char to uint8_t.
Where other kernel interfaces allow, migrate u_long to uint64_t.

No functional changes intended.

MFC-after: 1 week
Sponsored-by: The FreeBSD Foundation

vfs: use __enum_uint8 for vtype and vstate

This whacks hackery around only reading v_type once.

Bump __FreeBSD_version to 1400093

Explicitly initialize rather than reading newly allocated UFS inodes.

The function ffs_vgetf() is used to find or load UFS inodes into a
vnode. It first looks up the inode and if found in the cache its
vnode is returned. If it is not already in the cache, a new vnode
is allocated and its associated inode read in from the disk. The
read is done even for inodes that are being initially created.
The contents for the inode on the disk are assumed to be empty. If
the on-disk contents had been corrupted either due to a hardware
glitch or an agent deliberately trying to exploit the system, the
UFS code could panic from the unexpected partially-allocated inode.

Rather then having fsck_ffs(8) verify that all unallocated inodes
are properly empty, it is easier and quicker to add a flag to
ffs_vgetf() to indicate that the request is for a newly allocated
inode. When set, the disk read is skipped and the inode is set to
its expected empty (zero'ed out) initial state. As a side benefit,
an unneeded disk I/O is avoided.

Reported by: Peter Holm
Sponsored by: The FreeBSD Foundation

Move the ability to search for alternate UFS superblocks from fsck_ffs(8)
into ffs_sbsearch() to allow use by other parts of the system.

Historically only fsck_ffs(8), the UFS filesystem checker, had code
to track down and use alternate UFS superblocks. Since fsdb(8) used
much of the fsck_ffs(8) implementation it had some ability to track
down alternate superblocks.

This change extracts the code to track down alternate superblocks
from fsck_ffs(8) and puts it into a new function ffs_sbsearch() in
sys/ufs/ffs/ffs_subr.c. Like ffs_sbget() and ffs_sbput() also found
in ffs_subr.c, these functions can be used directly by the kernel
subsystems. Additionally they are exported to the UFS library,
libufs(8) so that they can be used by user-level programs. The new
functions added to libufs(8) are sbfind(3) that is an alternative
to sbread(3) and sbsearch(3) that is an alternative to sbget(3).
See their manual pages for further details.

The utilities that have been changed to search for superblocks are
dumpfs(8), fsdb(8), ffsinfo(8), and fsck_ffs(8). Also, the prtblknos(8)
tool found in tools/diag/prtblknos searches for superblocks.

The UFS specific mount code uses the superblock search interface
when mounting the root filesystem and when the administrator doing
a mount(8) command specifies the force flag (-f). The standalone UFS
boot code (found in stand/libsa/ufs.c) uses the superblock search
code in the hope of being able to get the system up and running so
that fsck_ffs(8) can be used to get the filesystem cleaned up.

The following utilities have not been changed to search for
superblocks: clri(8), tunefs(8), snapinfo(8), fstyp(8), quot(8),
dump(8), fsirand(8), growfs(8), quotacheck(8), gjournal(8), and
glabel(8). When these utilities fail, they do report the cause of
the failure. The one exception is the tasting code used to try and
figure what a given disk contains. The tasting code will remain
silent so as not to put out a slew of messages as it trying to taste
every new mass storage device that shows up.

Reviewed by: kib
Reviewed by: Warner Losh
Tested by: Peter Holm
Differential Revision: https://reviews.freebsd.org/D36053
Sponsored by: The FreeBSD Foundation

Add a flags parameter to the ffs_sbget() function that reads UFS superblocks.

Rather than trying to shoehorn flags into the requested superblock
address, create a separate flags parameter to the ffs_sbget()
function in sys/ufs/ffs/ffs_subr.c. The ffs_sbget() function is
used both in the kernel and in user-level utilities through export
to the sbget() function in the libufs(3) library (see sbget(3)
for details). The kernel uses ffs_sbget() when mounting UFS
filesystems, in the glabel(8) and gjournal(8) GEOM utilities,
and in the standalone library used when booting the system
from a UFS root filesystem.

The ffs_sbget() function reads the superblock located at the byte
offset specified by its sblockloc parameter. The value UFS_STDSB
may be specified for sblockloc to request that the standard
location for the superblock be read.

The two existing options are now flags:

UFS_NOHASHFAIL will note if the check hash is wrong but will still
return the superblock. This is used by the bootstrap code to
give the system a chance to come up so that fsck can be run to
correct the problem.

UFS_NOMSG indicates that superblock inconsistency error messages
should not be printed. It is used by programs like fsck that
want to print their own error message and programs like glabel(8)
that just want to know if a UFS filesystem exists on a partition.

One additional flag is added:

UFS_NOCSUM causes only the superblock itself to be returned, but does
not read in any auxiliary data structures like the cylinder group
summary information. It is used by clients like glabel(8) that
just want to check for possible filesystem types. Using UFS_NOCSUM
skips the superblock checks for csum data which allows superblocks
that have corrupted csum data to be read and used.

The validate_sblock() function checks that the superblock has not
been corrupted in a way that can crash or hang the system. Unless
the UFS_NOMSG flag is specified, it will print out any errors that
it finds. Prior to this commit, validate_sblock() returned as soon
as it found an inconsistency so would print at most one message.
It now does all its checks so when UFS_NOMSG has not been specified
will print out everything that it finds inconsistent.

Sponsored by: The FreeBSD Foundation

Consolodate four copies of the STDSB define into a single place.

The STDSB macro is passed to the ffs_sbget() routine to fetch a
UFS/FFS superblock "from the stadard place". It was identically defined
in lib/libufs/libufs.h, stand/libsa/ufs.c, sys/ufs/ffs/ffs_extern.h,
and sys/ufs/ffs/ffs_subr.c. Delete it from these four files and
define it instead in sys/ufs/ffs/fs.h. All existing uses of this macro
already include sys/ufs/ffs/fs.h so no include changes need to be made.

No functional change intended.

Sponsored by: Netflix

ffs: remove unused thread argument from ffs_reload()

MFC After: 1 week
Reviewed by: imp, kib
Differential Revision: https://reviews.freebsd.org/D31127

softdep_prelink(): only do sync if other thread changed the vnode metadata since previous prelink

We call into softdep_prerename() and softdep_prelink() when there is
low free space in the journal. Functions sync all vnodes participating
in the VOP, in the hope that this would reduce journal utilization. But
if the vnodes are already synced, doing sync would only spend writes,
journal is filled not due to the records from modifications of our
vnodes.

Remember original seqc numbers for vnodes, and only initiate syncs when
seqc changed.

Reviewed by: mckusick
Discussed with: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30041

ffs_extern.h: Add comments for ffs_vgetf() flags

Requested and reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D29178

Add FFSV_FORCEINODEDEP flag for ffs_vgetf()

It will be used to allow SU flush code to sync the volume while external
consumers see that SU is already disabled on the filesystem. Use it where
ffs_vgetf() called by SU code to process dependencies.

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D29178

ffs softdep: remove will_direnter argument of softdep_prelink()

Originally this was done in 8a1509e442bc9a075 to forcibly cover cases
where a hole in the directory could be created by extending into
indirect block, since dependency of writing out indirect block is not
tracked. This results in excessive amount of fsyncing the directories,
where all creation of new entry forced fsync before it. This is not needed,
it is enough to fsync when IN_NEEDSYNC is set, and VOP_VPUT_PAIR() provides
the required hook to only perform required syncing.

The series of changes culminating in this commit puts the performance of
metadata-intensive loads back to that before 8a1509e442bc9a075.

Analyzed by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

ffs_inotovp(): interface to convert (ino, gen) into alive vnode

It generalizes the VFS_FHTOVP() interface, making it possible to fetch
the inode without faking filehandle. Also it adds the ffs flags argument
which allows to control ffs_vgetf() call.

Requested by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

ffs: Add FFSV_REPLACE_DOOMED flag to ffs_vgetf()

It specifies that caller requests a fresh non-doomed vnode. If doomed
vnode is found in the hash, it should behave similarly to FFSV_REPLACE.
Or, to put it differently, the flag is same as FFSV_REPLACE, but only
when the found hashed vnode is doomed.

Reviewed by: chs, mkcusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

Handle LoR in flush_pagedep_deps().

When operating in SU or SU+J mode, ffs_syncvnode() might need to
instantiate other vnode by inode number while owning syncing vnode
lock. Typically this other vnode is the parent of our vnode, but due
to renames occuring right before fsync (or during fsync when we drop
the syncing vnode lock, see below) it might be no longer parent.

More, the called function flush_pagedep_deps() needs to lock other
vnode while owning the lock for vnode which owns the buffer, for which
the dependencies are flushed. This creates another instance of the
same LoR as was fixed in softdep_sync().

Put the generic code for safe relocking into new SU helper
get_parent_vp() and use it in flush_pagedep_deps(). The case for safe
relocking of two vnodes with undefined lock order was extracted into
vn helper vn_lock_pair().

Due to call sequence
ffs_syncvnode()->softdep_sync_buf()->flush_pagedep_deps(),
ffs_syncvnode() indicates with ERELOOKUP that passed vnode was
unlocked in process, and can return ENOENT if the passed vnode
reclaimed. All callers of the function were inspected.

Because UFS namei lookups store auxiliary information about directory
entry in in-memory directory inode, and this information is then used
by UFS code that creates/removed directory entry in the actual
mutating VOPs, it is critical that directory vnode lock is not dropped
between lookup and VOP. For softdep_prelink(), which ensures that
later link/unlink operation can proceed without overflowing the
journal, calls were moved to the place where it is safe to drop
processing VOP because mutations are not yet applied. Then, ERELOOKUP
causes restart of the whole VFS operation (typically VFS syscall) at
top level, including the re-lookup of the involved pathes. [Note that
we already do the same restart for failing calls to vn_start_write(),
so formally this patch does not introduce new behavior.]

Similarly, unsafe calls to fsync in snapshot creation code were
plugged. A possible view on these failures is that it does not make
sense to continue creating snapshot if the snapshot vnode was
reclaimed due to forced unmount.

It is possible that relock/ERELOOKUP situation occurs in
ffs_truncate() called from ufs_inactive(). In this case, dropping the
vnode lock is not safe. Detect the situation with VI_DOINGINACT and
reschedule inactivation by setting VI_OWEINACT. ufs_inactive()
rechecks VI_OWEINACT and avoids reclaiming vnode is truncation failed
this way.

In ffs_truncate(), allocation of the EOF block for partial truncation
is re-done after vnode is synced, since we cannot leave the buffer
locked through ffs_syncvnode().

In collaboration with: pho
Reviewed by: mckusick (previous version), markj
Tested by: markj (syzkaller), pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26136

ufs: clean up empty lines in .c and .h files

Move all of the functions in ffs_subr.c that are only used by the ufs kernel
module from that file into ffs_vfsops.c. This fixes the build for kernel
configs that don't include FFS.

PR: 247256
Submitted by: glebius
Reviewed by: mckusick (earlier version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D25285

This commit enables a UFS filesystem to do a forcible unmount when
the underlying media fails or becomes inaccessible. For example
when a USB flash memory card hosting a UFS filesystem is unplugged.

The strategy for handling disk I/O errors when soft updates are
enabled is to stop writing to the disk of the affected file system
but continue to accept I/O requests and report that all future
writes by the file system to that disk actually succeed. Then
initiate an asynchronous forced unmount of the affected file system.

There are two cases for disk I/O errors:

- ENXIO, which means that this disk is gone and the lower layers
of the storage stack already guarantee that no future I/O to
this disk will succeed.

- EIO (or most other errors), which means that this particular
I/O request has failed but subsequent I/O requests to this
disk might still succeed.

For ENXIO, we can just clear the error and continue, because we
know that the file system cannot affect the on-disk state after we
see this error. For EIO or other errors, we arrange for the geom_vfs
layer to reject all future I/O requests with ENXIO just like is
done when the geom_vfs is orphaned. In both cases, the file system
code can just clear the error and proceed with the forcible unmount.

This new treatment of I/O errors is needed for writes of any buffer
that is involved in a dependency. Most dependencies are described
by a structure attached to the buffer's b_dep field. But some are
created and processed as a result of the completion of the dependencies
attached to the buffer.

Clearing of some dependencies require a read. For example if there
is a dependency that requires an inode to be written, the disk block
containing that inode must be read, the updated inode copied into
place in that buffer, and the buffer then written back to disk.

Often the needed buffer is already in memory and can be used. But
if it needs to be read from the disk, the read will fail, so we
fabricate a buffer full of zeroes and pretend that the read succeeded.
This zero'ed buffer can be updated and written back to disk.

The only case where a buffer full of zeros causes the code to do
the wrong thing is when reading an inode buffer containing an inode
that still has an inode dependency in memory that will reinitialize
the effective link count (i_effnlink) based on the actual link count
(i_nlink) that we read. To handle this case we now store the i_nlink
value that we wrote in the inode dependency so that it can be
restored into the zero'ed buffer thus keeping the tracking of the
inode link count consistent.

Because applications depend on knowing when an attempt to write
their data to stable storage has failed, the fsync(2) and msync(2)
system calls need to return errors if data fails to be written to
stable storage. So these operations return ENXIO for every call
made on files in a file system where we have otherwise been ignoring
I/O errors.

Coauthered by: mckusick
Reviewed by: kib
Tested by: Peter Holm
Approved by: mckusick (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D24088

Update ffs_getcg() function to accept a flags parameter to be passed
to breadn_flags() in preparation for later need when doing forcible
unmount when disk dies or is removed.

No functional change.

Sponsored by: Netflix

UFS: stop reusing the vnode for reallocated inode.

In ffs_valloc(), force reclaim existing vnode on inode reuse, instead
of trying to re-initialize the same vnode for new purposes. This is
done in preparation of changes to the vp->v_object lifecycle handling.

A new FFSV_REPLACE flag to ffs_vgetf() directs the function to
vgone(9) the vnode if found in vfs hash, instead of returning it.

Reviewed by: markj, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21412

The error reported in FS-14-UFS-3 can only happen on UFS/FFS
filesystems that have block pointers that are out-of-range for their
filesystem. These out-of-range block pointers are corrected by
fsck(8) so are only encountered when an unchecked filesystem is
mounted.

A new "untrusted" flag has been added to the generic mount interface
that can be set when mounting media of unknown provenance or integrity.
For example, a daemon that automounts a filesystem on a flash drive
when it is plugged into a system.

This commit adds a test to UFS/FFS that validates all block numbers
before using them. Because checking for out-of-range blocks adds
unnecessary overhead to normal operation, the tests are only done
when the filesystem is mounted as an "untrusted" filesystem.

Reported by: Christopher Krah, Thomas Barabosch, and Jan-Niclas Hilgert of Fraunhofer FKIE
Reported as: FS-14-UFS-3: Out of bounds read in write-2 (ffs_alloccg)
Reviewed by: kib
Sponsored by: Netflix

Continuing efforts to provide hardening of FFS. This change adds a
check hash to the filesystem inodes. Access attempts to files
associated with an inode with an invalid check hash will fail with
EINVAL (Invalid argument). Access is reestablished after an fsck
is run to find and validate the inodes with invalid check-hashes.
This check avoids a class of filesystem panics related to corrupted
inodes. The hash is done using crc32c.

Note this check-hash is for the inode itself and not any of its
indirect blocks. Check-hash validation may be extended to also
cover indirect block pointers, but that will be a separate (and
more costly) feature.

Check hashes are added only to UFS2 and not to UFS1 as UFS1 is
primarily used in embedded systems with small memories and low-powered
processors which need as light-weight a filesystem as possible.

Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix

Normally when an attempt is made to mount a UFS/FFS filesystem whose
superblock has a check-hash error, an error message noting the
superblock check-hash failure is printed and the mount fails. The
administrator then runs fsck to repair the filesystem and when
successful, the filesystem can once again be mounted.

This approach fails if the filesystem in question is a root filesystem
from which you are trying to boot. Here, the loader fails when trying
to access the filesystem to get the kernel to boot. So it is necessary
to allow the loader to ignore the superblock check-hash error and make
a best effort to read the kernel. The filesystem may be suffiently
corrupted that the read attempt fails, but there is no harm in trying
since the loader makes no attempt to write to the filesystem.

Once the kernel is loaded and starts to run, it attempts to mount its
root filesystem. Once again, failure means that it breaks to its prompt
to ask where to get its root filesystem. Unless you have an alternate
root filesystem, you are stuck.

Since the root filesystem is initially mounted read-only, it is
safe to make an attempt to mount the root filesystem with the failed
superblock check-hash. Thus, when asked to mount a root filesystem
with a failed superblock check-hash, the kernel prints a warning
message that the root filesystem superblock check-hash needs repair,
but notes that it is ignoring the error and proceeding. It does
mark the filesystem as needing an fsck which prevents it from being
enabled for writing until fsck has been run on it. The net effect
is that the reboot fails to single user, but at least at that point
the administrator has the tools at hand to fix the problem.

Reported by: Rick Macklem (rmacklem@)
Discussed with: Warner Losh (imp@)
Sponsored by: Netflix

Calculate updated superblock check-hash before writing it into the snapshot.
This corrects a bug that prevented snapshots from being mounted due to a
superblock check-hash failure.

Reported by: Brennan Vincent <brennan@umanwizard.com>
Tested by: Peter Holm (pho@)
Sponsored by: Netflix

In preparation for adding inode check-hashes, clean up and
document the libufs interface for fetching and storing inodes.
The undocumented getino / putino interface has been replaced
with a new getinode / putinode interface.

Convert the utilities that had been using the undocumented
interface to use the new documented interface.

No functional change (as for now the libufs library does not
do inode check-hashes).

Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix

Replace the TRIM consolodation framework originally added in -r337396
driven by problems found with the algorithms being tested for TRIM
consolodation.

Reported by: Peter Holm
Suggested by: kib
Reviewed by: kib
Sponsored by: Netflix

Revert -r337396. It is being replaced with a revised interface that
resulted from testing and further reviews.

Put in place the framework for consolodating contiguous blocks into
a smaller number of larger TRIM requests. The hope had been to have
the full TRIM consolodation in place for 12.0, but the algorithms
are still under development and need further testing. With this
framework in place it will be possible to easily add TRIM consolodation
once the optimal strategy has been found.

The only functional change with this patch is the elimination of TRIM
requests for blocks that are freed before they have been likely to
have been written.

Reviewed by: kib
Discussed with: Warner Losh and Chuck Silvers
Sponsored by: Netflix

Refactoring of reading and writing of the UFS/FFS superblock.
Specifically reading is done if ffs_sbget() and writing is done
in ffs_sbput(). These functions are exported to libufs via the
sbget() and sbput() functions which then used in the various
filesystem utilities. This work is in preparation for adding
subperblock check hashes.

No functional change intended.

Reviewed by: kib

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Create a new function ffs_getcg() to read in and verify a cylinder
group. Change all code points that open-coded this functionality
to use the new function. This commit is a refactoring with no
change in functionality.

In the future this change allows more robust checking of cylinder
group reads along the lines discussed in the hardening UFS session
at BSDCan (retry I/O, add checksums, etc). For more detail see the
session notes at https://wiki.freebsd.org/DevSummit/201706/HardeningUFS

Reviewed by: kib

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

Partially lift suspension when ffs_reload() finished with cgs and
going to re-read inodes.

Secondary write initiators, e.g. ufs_inactive(), might need to start a
write while owning the vnode lock. Since the suspended state
established by /dev/ufssuspend prevents them from entering
vn_start_secondary_write(), we get deadlock otherwise.

Note that it is arguably not very useful to re-read inodes after
/dev/ufssuspend suspension, because the suspension does not block
readers, and other threads might read existing files in parallel with
suspension owner (for now, only growfs(8)) operations. This
effectively means that suspension owner cannot safely modify existing
inodes, and then there is no sense in re-reading. But keep the code
enabled for now.

Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

Implement VOP_FDATASYNC() for UFS.

Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D7471

Remove ffs_mountroot() prototype; seems to be long gone.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

ufs: small formatting fixes.

Cleanup some extra space.
Use of tabs vs. spaces.
No functional change.

MFC after: 3 days
Reviewed by: mckusick

First of several cleanups to soft dependency implementation.
Convert three functions exported from ffs_softdep.c to static
functions as they are not used outside of ffs_softdep.c.

No functional change.

Tested by: Peter Holm and Scott Long
Sponsored by: Netflix

Add UFS writesuspension mechanism, designed to allow userland processes
to modify on-disk metadata for filesystems mounted for write.

Reviewed by: kib, mckusick
Sponsored by: FreeBSD Foundation

Remove unused thread argument from vtruncbuf().

Reviewed by: kib

Add a third flags argument to ffs_syncvnode to avoid a possible conflict
with MNT_WAIT flags that passed in its second argument. This will be
MFC'ed together with r232351.

Discussed with: kib

This change avoids a kernel deadlock on "snaplk" when using
snapshots on UFS filesystems running with journaled soft updates.
This is the first of several bugs that need to be fixed before
removing the restriction added in -r230250 to prevent the use
of snapshots on filesystems running with journaled soft updates.

The deadlock occurs when holding the snapshot lock (snaplk)
and then trying to flush an inode via ffs_update(). We become
blocked by another process trying to flush a different inode
contained in the same inode block that we need. It holds the
inode block for which we are waiting locked. When it tries to
write the inode block, it gets blocked waiting for the our
snaplk when it calls ffs_copyonwrite() to see if the inode
block needs to be copied in our snapshot.

The most obvious place that this deadlock arises is in the
ffs_copyonwrite() routine when it updates critical metadata
in a snapshot and tries to write it out before proceeding.
The fix here is to write the data and indirect block pointer
for the snapshot, but to skip the call to ffs_update() to
write the snapshot inode. To ensure that we will never have
to update a pointer in the inode itself, the ffs_snapshot()
routine that creates the snapshot has to ensure that all the
direct blocks are allocated as part of the creation of the
snapshot.

A less obvious place that this deadlock occurs is when we hold
the snaplk because we are deleting a snapshot. In the course of
doing the deletion, we need to allocate various soft update
dependency structures and allocate some journal space. If we
hit a resource limit while doing this we decrease the resources
in use by flushing out an existing dirty file to get it to give
up the soft dependency resources that it holds. The flush can
cause an ffs_update() to be done on the inode for the file that
we have selected to flush resulting in the same deadlock as
described above when the inode that we have chosen to flush
resides in the same inode block as the snapshot inode that we hold.
The fix is to defer cleaning up any time that the inode on which
we are operating is a snapshot.

Help and review by: Jeff Roberson
Tested by: Peter Holm
MFC (to 9 only) after: 2 weeks

Generalize ffs_pages_remove() into vn_pages_remove().

Remove mapped pages for all dataset vnodes in zfs_rezget() using
new vn_pages_remove() to fix mmapped files changed by
zfs rollback or zfs receive -F.

PR: kern/160035, kern/156933
Reviewed by: kib, pjd
Approved by: re (kib)
MFC after: 1 week

- Fix directory count rollbacks by passing the mode to the journal dep
earlier.
- Add rollback/forward code for frag and cluster accounting.
- Handle the FREEDEP case in softdep_sync_buf(). (submitted by pho)

Drop the include of <ufs/ffs/ffs_extern.h> from usr.sbin/makefs/ffs/ffs_bswap.c
and usr.sbin/makefs/ffs/ffs_subr.c as they have no need of anything in that
file. No other programs or libraries include <ufs/ffs/ffs_extern.h> (nor
should they as it is totally in-kernel interfaces). For added protection
I enclosed the entire contents of <ufs/ffs/ffs_extern.h> in ifdef _KERNEL.

Feedback from: Bruce Evans and Tai-hwa Liang

Fixing compilation bustage by introducing another forward declaration.

Ensure that filesystem metadata contained within persistent snapshots
is always kept consistent.

Suggested by: Jeff Roberson

With the restructuring of the block reclaimation code, the notification
messages for a filesystem being out of space need to be moved so that
they do not print out until after a failed cleanup attempt.

Suggested by: Jeff Roberson

Use alternative, less messy solution to avoid breakage after r223020:
put the snapdata structure between #ifdef _KERNEL guards.

Suggested by: kib

Update to soft updates journaling to properly track freed blocks
that get claimed by snapshots.

Submitted by: Jeff Roberson
Tested by: Peter Holm

Implement fully asynchronous partial truncation with softupdates journaling
to resolve errors which can cause corruption on recovery with the old
synchronous mechanism.

- Append partial truncation freework structures to indirdeps while
truncation is proceeding. These prevent new block pointers from
becoming valid until truncation completes and serialize truncations.
- On completion of a partial truncate journal work waits for zeroed
pointers to hit indirects.
- softdep_journal_freeblocks() handles last frag allocation and last
block zeroing.
- vtruncbuf/ffs_page_remove moved into softdep_*_freeblocks() so it
is only implemented in one place.
- Block allocation failure handling moved up one level so it does not
proceed with buf locks held. This permits us to do more extensive
reclaims when filesystem space is exhausted.
- softdep_sync_metadata() is broken into two parts, the first executes
once at the start of ffs_syncvnode() and flushes truncations and
inode dependencies. The second is called on each locked buf. This
eliminates excessive looping and rollbacks.
- Improve the mechanism in process_worklist_item() that handles
acquiring vnode locks for handle_workitem_remove() so that it works
more generally and does not loop excessively over the same worklist
items on each call.
- Don't corrupt directories by zeroing the tail in fsck. This is only
done for regular files.
- Push a fsync complete record for files that need it so the checker
knows a truncation in the journal is no longer valid.

Discussed with: mckusick, kib (ffs_pages_remove and ffs_truncate parts)
Tested by: pho

Be far more persistent in reclaiming blocks and inodes before giving
up and declaring a filesystem out of space. Especially necessary when
running on a small filesystem. With this improvement, it should be
possible to use soft updates on a small root filesystem.

Kudos to: Peter Holm
Testing by: Peter Holm
MFC: 2 weeks

Add retry code analogous to the block allocation retry code
to avoid running out of inodes.

Reported by: Peter Holm

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Merge soft-updates journaling from projects/suj/head into head. This
brings in support for an optional intent log which eliminates the need
for background fsck on unclean shutdown.

Sponsored by: iXsystems, Yahoo!, and Juniper.
With help from: McKusick and Peter Holm

Following a fair amount of real world experience with ACLs and
extended attributes since FreeBSD 5, make the following semantic
changes:

- Don't update the inode modification time (mtime) when extended
attributes (and hence also ACLs) are added, modified, or removed.
- Don't update the inode access tie (atime) when extended attributes
(and hence also ACLs) are queried.

This means that rsync (and related tools) won't improperly think
that the data in the file has changed when only the ACL has changed.

Note that ffs_reallocblks() has not been changed to not update on an
IO_EXT transaction, but currently EAs don't use the cluster write
routines so this shouldn't be a problem. If EAs grow support for
clustering, then VOP_REALLOCBLKS() will need to grow a flag argument
to carry down IO_EXT to UFS.

MFC after: 1 week
PR: ports/125739
Reported by: Alexander Zagrebin <alexz@visp.ru>
Tested by: pluknet <pluknet@gmail.com>,
Greg Byshenk <freebsd@byshenk.net>
Discussed with: kib, kientzle, timur, Alexander Bokovoy <ab@samba.org>

Apply the big hammer:
o remove all of compat except for pwcache and strstuftoll; these might
end up in libutil or similar so keep them in the subdir
o mv getid.c up to the top level; this looks like something that'll be
makefs-specific
o eliminate private versions of .h files in sys; use system files instead
o eliminate private ffs_tables.c; use the system version directly (might
want to adopt const'ification at some point but that's the only diff I
can see)
o mv remaining code from sys to ffs and strip out unused bits; this now
becomes part of makefs
o add compat defs and shims to makefs.h
o strip all vestiges of nbtool_config.h, compat_defs.h, etc.
o fixup includes after file shuffling
o rename system #defines that do implicit byte swapping to have an _swap
suffix; e.g. DIRSIZ -> DIRSIZ_SWAP, cg_inosused -> cg_inosused_swap; if
we ever add endian-agnostic support to the kernel these can go back to
their original names
o strip some netbsd'isms that aren't worth shim'ing (e.g. _DIAGASSERT)

Code compiles w/o complaints but is untested.

prepare makefs for import to base

- Import the HEAD csup code which is the basis for the cvsmode work.

When attempt is made to suspend a filesystem that is already syspended,
wait until the current suspension is lifted instead of silently returning
success immediately. The consequences of calling vfs_write() resume when
not owning the suspension are not well-defined at best.

Add the vfs_susp_clean() mount method to be called from
vfs_write_resume(). Set it to process_deferred_inactive() for ffs, and
stop calling it manually.

Add the thread flag TDP_IGNSUSP that allows to bypass the suspension
point in the vn_start_write. It is intended for use by VFS in the
situations where the suspender want to do some i/o requiring calls to
vn_start_write(), and this i/o cannot be done later.

Reviewed by: tegge
In collaboration with: pho
MFC after: 1 month

When downgrading the read-write mount to read-only, do_unmount() sets
MNT_RDONLY flag before the VFS_MOUNT() is called. In ufs_inactive()
and ufs_itimes_locked(), UFS verifies whether the fs is read-only by
checking MNT_RDONLY, but this may cause loss of the IN_MODIFIED flag
for inode on the fs being remounted rw->ro.

Introduce UFS_RDONLY() struct ufsmount' method that reports the value
of the fs_ronly. The later is set to 1 only after the remount is
finished.

Reviewed by: tegge
In collaboration with: pho
MFC after: 1 month

Softdep code may need to instantiate vnode when processing
dependencies. In particular, it may need this while syncing filesystem
being unmounted. Since during unmount MNTK_NOINSMNTQUE flag is set,
that could sometimes disallow insertion of the vnode into the vnode
mount list, softdep code needs to overwrite the MNTK_NOINSMNTQUE flag.

Create the ffs_vgetf() function that sets the VV_FORCEINSMQ flag for
new vnode and use it consistently from the softdep code instead of
ffs_vget().

Add the retry logic to the softdep_flushfiles() to flush the vnodes
that could be instantiated while flushing softdep dependencies.

Tested by: pho, kris
Reviewed by: tegge
MFC after: 1 month

Cylinder group bitmaps and blocks containing inode for a snapshot
file are after snaplock, while other ffs device buffers are before
snaplock in global lock order. By itself, this could cause deadlock
when bdwrite() tries to flush dirty buffers on snapshotted ffs. If,
during the flush, COW activity for snapshot needs to allocate block
and ffs_alloccg() selects the cylinder group that is being written
by bdwrite(), then kernel would panic due to recursive buffer lock
acquision.

Avoid dealing with buffers in bdwrite() that are from other side of
snaplock divisor in the lock order then the buffer being written. Add
new BOP, bop_bdwrite(), to do dirty buffer flushing for same vnode in
the bdwrite(). Default implementation, bufbdflush(), refactors the code
from bdwrite(). For ffs device buffers, specialized implementation is
used.

Reviewed by: tegge, jeff, Russell Cattelan (cattelan xfs org, xfs changes)
Tested by: Peter Holm
X-MFC after: 3 weeks (if ever: it changes ABI)

Add gjournal specific code to the UFS file system:
- Add FS_GJOURNAL flag which enables gjournal support on a file system.
- Add cg_unrefs field to the cylinder group structure which holds
number of unreferenced (orphaned) inodes in the given cylinder group.
- Add fs_unrefs field to the super block structure which holds
total number of unreferenced (orphaned) inodes.
- When file or a directory is orphaned (last reference is removed, but
object is still open), increase fs_unrefs and cg_unrefs fields,
which is a hint for fsck in which cylinder groups looks for such
(orphaned) objects.
- When file is last closed, decrease {fs,cg}_unrefs fields.
- Add VV_DELETED vnode flag which points at orphaned objects.

Sponsored by: home.pl

Use vn_start_secondary_write() and vn_finished_secondary_write() as a
replacement for vn_write_suspend_wait() to better account for secondary write
processing.

Close race where secondary writes could be started after ffs_sync() returned
but before the file system was marked as suspended.

Detect if secondary writes or softdep processing occurred during vnode sync
loop in ffs_sync() and retry the loop if needed.

- Move softdep from using a global worklist to per-mount worklists. This
has many positive effects including improved smp locking, reducing
interdependencies between mounts that can lead to deadlocks, etc.
- Add the softdep worklist and various counters to the ufsmnt structure.
- Add a mount pointer to the workitem and remove mount pointers from the
various structures derived from the workitem as they are now redundant.
- Remove the poor-man's semaphore protecting softdep_process_worklist and
softdep_flushworklist. Several threads may now process the list
simultaneously.
- Add softdep_waitidle() to block the thread until all pending
dependencies being operated on by other threads have been flushed.
- Use softdep_waitidle() in unmount and snapshots to block either
operation until the fs is stable.
- Remove softdep worklist processing from the syncer and move it into the
softdep_flush() thread. This thread processes all softdep mounts
once each second and when it is called via the new softdep_speedup()
when there is a resource shortage. This removes the softdep hook
from the kernel and various hacks in header files to support it.

Reviewed by/Discussed with: tegge, truckman, mckusick
Tested by: kris

- Move the contents of softdep_disk_prewrite into ffs_geom_strategy to fix
two bugs.
- ffs_disk_prewrite was pulling the vp from the buf and checking for
COPYONWRITE, when really it wanted the vp from the bufobj that we're
writing to, which is the devvp. This lead to us skipping the copy on
write to all file data, which significantly broke snapshots for the
last few months.
- When the SOFTUPDATES option was not included in the kernel config we
would also skip the copy on write check, which would effectively disable
snapshots.
- Remove an invalid mp_fixme().

Debugging tips from: mckusick
Reported by: iedowse, others
Discussed with: phk

Make a some SYSCTL_NODEs and some of FFS's VFS_ methods static.

Split the vop_vector for ffs1 and ffs2, this is mostly for the different
EXTATTR support.

Background writes are entirely an FFS/Softupdates thing.

Give FFS vnodes a specific bufwrite method which contains all the
background write stuff and then calls into the default bufwrite()
for the rest of the job.

Remove all the background write related stuff from the normal bufwrite.

This drags the softdep_move_dependencies() back into FFS.

Long term, it is worth looking at simply copying the data into
allocated memory and issuing the bio directly and not create the
"shadow buf" in the first place (just like copy-on-write is done
in snapshots for instance). I don't think we really gain anything
but complexity from doing this with a buf.

For snapshots we need all VOP_LOCKs to be exclusive.

The "business class upgrade" was implemented in UFS's VOP_LOCK
implementation ufs_lock() which is the wrong layer, so move it to
ffs_lock().

Also, as long as we have not abandonned advanced vfs-stacking we
should not preclude it from happening: instead of implementing a
copy locally, use the VOP_LOCK_APV(&ufs) to correctly arrive at
vop_stdlock() at the bottom.

- Change some function parameters so that the ufsmount structure is
accessable in places where the ufs lock will be needed.

Sponsored By: Isilon Systems, Inc.

Back when VOP_* was introduced, we did not have new-style struct
initializations but we did have lofty goals and big ideals.

Adjust to more contemporary circumstances and gain type checking.

Replace the entire vop_t frobbing thing with properly typed
structures. The only casualty is that we can not add a new
VOP_ method with a loadable module. History has not given
us reason to belive this would ever be feasible in the the
first place.

Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc.

Give coda correct prototypes and function definitions for
all vop_()s.

Generate a bit more data from the vnode_if.src file: a
struct vop_vector and protype typedefs for all vop methods.

Add a new vop_bypass() and make vop_default be a pointer
to another struct vop_vector.

Remove a lot of vfs_init since vop_vector is ready to use
from the compiler.

Cast various vop_mumble() to void * with uppercase name,
for instance VOP_PANIC, VOP_NULL etc.

Implement VCALL() by making vdesc_offset the offsetof() the
relevant function pointer in vop_vector. This is disgusting
but since the code is generated by a script comparatively
safe. The alternative for nullfs etc. would be much worse.

Fix up all vnode method vectors to remove casts so they
become typesafe. (The bulk of this is generated by scripts)

Move UFS from DEVFS backing to GEOM backing.

This eliminates a bunch of vnode overhead (approx 1-2 % speed
improvement) and gives us more control over the access to the storage
device.

Access counts on the underlying device are not correctly tracked and
therefore it is possible to read-only mount the same disk device multiple
times:
syv# mount -p
/dev/md0 /var ufs rw 2 2
/dev/ad0 /mnt ufs ro 1 1
/dev/ad0 /mnt2 ufs ro 1 1
/dev/ad0 /mnt3 ufs ro 1 1

Since UFS/FFS is not a synchrousely consistent filesystem (ie: it caches
things in RAM) this is not possible with read-write mounts, and the system
will correctly reject this.

Details:

Add a geom consumer and a bufobj pointer to ufsmount.

Eliminate the vnode argument from softdep_disk_prewrite().
Pick the vnode out of bp->b_vp for now. Eventually we
should find it through bp->b_bufobj->b_private.

In the mountcode, use g_vfs_open() once we have used
VOP_ACCESS() to check permissions.

When upgrading and downgrading between r/o and r/w do the
right thing with GEOM access counts. Remove all the
workarounds for not being able to do this with VOP_OPEN().

If we are the root mount, drop the exclusive access count
until we upgrade to r/w. This allows fsck of the root
filesystem and the MNT_RELOAD to work correctly.

Set bo_private to the GEOM consumer on the device bufobj.

Change the ffs_ops->strategy function to call g_vfs_strategy()

In ufs_strategy() directly call the strategy on the disk
bufobj. Same in rawread.

In ffs_fsync() we will no longer see VCHR device nodes, so
remove code which synced the filesystem mounted on it, in
case we came there. I'm not sure this code made sense in
the first place since we would have taken the specfs route
on such a vnode.

Redo the highly bogus readblock() function in the snapshot
code to something slightly less bogus: Constructing an uio
and using physio was really quite a detour. Instead just
fill in a bio and ship it down.

The island council met and voted buf_prewrite() home.

Give ffs it's own bufobj->bo_ops vector and create a private strategy
routine, (currently misnamed for forwards compatibility), which is
just a copy of the generic bufstrategy routine except we call
softdep_disk_prewrite() directly instead of through the buf_prewrite()
indirection.

Teach UFS about the need for softdep_disk_prewrite() and call the
function directly in FFS.

Remove buf_prewrite() from the default bufstrategy() and from the
global bio_ops method vector.

Degeneralize the per cdev copyonwrite callback. The only possible value
is ffs_copyonwrite() and the only place it can be called from is FFS which
would never want to call another filesystems copyonwrite method, should one
exist, so there is no reason why anything generic should know about this.

Remove support for accessing device nodes in UFS/FFS.

Device nodes can still be created and exported with NFS.

Put a version element in the VFS filesystem configuration structure
and refuse initializing filesystems with a wrong version. This will
aid maintenance activites on the 5-stable branch.

s/vfs_mount/vfs_omount/

s/vfs_nmount/vfs_mount/

Name our filesystems mount function consistently.

Eliminate the namiedata argument to both vfs_mount and vfs_omount.
It was originally there to save stack space. A few places abused
it to get hold of some credentials to pass around. Effectively
it is unused.

Reorganize the root filesystem selection code.

Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and irc message from Robert
Watson saying that clause 3 can be removed from those files with an
NAI copyright that also have only a University of California
copyrights.

Approved by: core, rwatson

This patch fixes a bug on an active filesystem on which a snapshot
is being taken from panicing with either "freeing free block" or
"freeing free inode". The problem arises when the snapshot code
is scanning the filesystem looking for inodes with a reference
count of zero (e.g., unlinked but still open) so that it can
expunge them from its view. If it encounters a reclaimed vnode
and has to restart its scan, then it will panic if it encounters
and tries to free an inode that it has already processed. The fix
is to check each candidate inode to see if it has already been
processed before trying to delete it from the snapshot image.

Sponsored by: DARPA & NAI Labs.

Move the allocation of the inode contents into ffs_vfsops.c rather than
passing malloc types around.

Make ffs_mountfs() static.

Remove the malloctype from the ufs mount structure, instead add a callback
to the storage method for freeing inodes: UFS_IFREE().

Add vfs_ifree() method function which frees an inode.

Unvariablelize the malloc type used for allocating inodes.

Introduce typedefs for the member functions of struct vfsops and employ
these in the main filesystems. This does not change the resulting code
but makes the source a little bit more grepable.

Sponsored by: DARPA and NAI Labs.

Move ffs_isfreeblock() to ffs_alloc.c and make it static.

Sponsored by: DARPA & NAI Labs.

Add support to UFS2 to provide storage for extended attributes.
As this code is not actually used by any of the existing
interfaces, it seems unlikely to break anything (famous
last words).

The internal kernel interface to manipulate these attributes
is invoked using two new IO_ flags: IO_NORMAL and IO_EXT.
These flags may be specified in the ioflags word of VOP_READ,
VOP_WRITE, and VOP_TRUNCATE. Specifying IO_NORMAL means that
you want to do I/O to the normal data part of the file and
IO_EXT means that you want to do I/O to the extended attributes
part of the file. IO_NORMAL and IO_EXT are mutually exclusive
for VOP_READ and VOP_WRITE, but may be specified individually
or together in the case of VOP_TRUNCATE. For example, when
removing a file, VOP_TRUNCATE is called with both IO_NORMAL
and IO_EXT set. For backward compatibility, if neither IO_NORMAL
nor IO_EXT is set, then IO_NORMAL is assumed.

Note that the BA_ and IO_ flags have been `merged' so that they
may both be used in the same flags word. This merger is possible
by assigning the IO_ flags to the low sixteen bits and the BA_
flags the high sixteen bits. This works because the high sixteen
bits of the IO_ word is reserved for read-ahead and help with
write clustering so will never be used for flags. This merge
lets us get away from code of the form:

if (ioflags & IO_SYNC)
flags |= BA_SYNC;

For the future, I have considered adding a new field to the
vattr structure, va_extsize. This addition could then be
exported through the stat structure to allow applications to
find out the size of the extended attribute storage and also
would provide a more standard interface for truncating them
(via VOP_SETATTR rather than VOP_TRUNCATE).

I am also contemplating adding a pathconf parameter (for
concreteness, lets call it _PC_MAX_EXTSIZE) which would
let an application determine the maximum size of the extended
atribute storage.

Sponsored by: DARPA & NAI Labs.

Add the ffs bits necessary to support unloading of the ufs kernel
module. This adds an ffs_uninit() function that calls ufs_uninit()
and also calls a new softdep_uninitialize() function. Add a stub
for softdep_uninitialize() to cover the non-SOFTUPDATES case.

Reviewed by: mckusick

This commit adds basic support for the UFS2 filesystem. The UFS2
filesystem expands the inode to 256 bytes to make space for 64-bit
block pointers. It also adds a file-creation time field, an ability
to use jumbo blocks per inode to allow extent like pointer density,
and space for extended attributes (up to twice the filesystem block
size worth of attributes, e.g., on a 16K filesystem, there is space
for 32K of attributes). UFS2 fully supports and runs existing UFS1
filesystems. New filesystems built using newfs can be built in either
UFS1 or UFS2 format using the -O option. In this commit UFS1 is
the default format, so if you want to build UFS2 format filesystems,
you must specify -O 2. This default will be changed to UFS2 when
UFS2 proves itself to be stable. In this commit the boot code for
reading UFS2 filesystems is not compiled (see /sys/boot/common/ufsread.c)
as there is insufficient space in the boot block. Once the size of the
boot block is increased, this code can be defined.

Things to note: the definition of SBSIZE has changed to SBLOCKSIZE.
The header file <ufs/ufs/dinode.h> must be included before
<ufs/ffs/fs.h> so as to get the definitions of ufs2_daddr_t and
ufs_lbn_t.

Still TODO:
Verify that the first level bootstraps work for all the architectures.
Convert the utility ffsinfo to understand UFS2 and test growfs.
Add support for the extended attribute storage. Update soft updates
to ensure integrity of extended attribute storage. Switch the
current extended attribute interfaces to use the extended attribute
storage. Add the extent like functionality (framework is there,
but is currently never used).

Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@freebsd.org>

Remove __P.

Add a flags parameter to VFS_VGET to pass through the desired
locking flags when acquiring a vnode. The immediate purpose is
to allow polling lock requests (LK_NOWAIT) needed by soft updates
to avoid deadlock when enlisting other processes to help with
the background cleanup. For the future it will allow the use of
shared locks for read access to vnodes. This change touches a
lot of files as it affects most filesystems within the system.
It has been well tested on FFS, loopback, and CD-ROM filesystems.
only lightly on the others, so if you find a problem there, please
let me (mckusick@mckusick.com) know.

When taking a snapshot, we must check for active files that have
been unlinked (e.g., with a zero link count). We have to expunge
all trace of these files from the snapshot so that they are neither
reclaimed prematurely by fsck nor saved unnecessarily by dump.

This patch fixes a long standing complaint with soft updates in
which small and/or nearly full filesystems would fail with `file
system full' messages when trying to replace a number of existing
files (for example during a system installation). When the allocation
routines are about to fail with a file system full condition, they
make a call to softdep_request_cleanup() which attempts to accelerate
the flushing of pending deletion requests in an effort to free up
space. In the face of filesystem I/O requests that exceed the
available disk transfer capacity, the cleanup request could take
an unbounded amount of time. Thus, the softdep_request_cleanup()
routine will only try for tickdelay seconds (default 2 seconds)
before giving up and returning a filesystem full error. Under typical
conditions, the softdep_request_cleanup() routine is able to free
up space in under fifty milliseconds.

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

Forward declare struct cg to quiet a warning.

Submitted by: bde

Refinement to revision 1.16 of ufs/ffs/ffs_snapshot.c to reduce
the amount of time that the filesystem must be suspended. The
current snapshot is elided as well as the earlier snapshots.

VOP_BALLOC was never really a VOP in the first place, so convert it
to UFS_BALLOC like the other "between UFS and FFS function interfaces".

Remove faint traces of non-existant ffs_bmap().

Add kernel support for running fsck on active filesystems.

Fixes to track snapshot copy-on-write checking in the specinfo
structure rather than assuming that the device vnode would reside
in the FFS filesystem (which is obviously a broken assumption with
the device filesystem).

Several small but important fixes for snapshots:

1) Be more tolerant of missing snapshot files by only trying to decrement
their reference count if they are registered as active.

2) Fix for snapshots of filesystems with block sizes larger than 8K
(from Ollivier Robert <roberto@eurocontrol.fr>).

3) Fix to avoid losing last block in snapshot file when calculating blocks
that need to be copied (from Don Coleman <coleman@coleman.org>).

Initial commit of IFS - a inode-namespaced FFS. Here is a short
description:

How it works:
--

Basically ifs is a copy of ffs, overriding some vfs/vnops. (Yes, hack.)
I didn't see the need in duplicating all of sys/ufs/ffs to get this
off the ground.

File creation is done through a special file - 'newfile' . When newfile
is called, the system allocates and returns an inode. Note that newfile
is done in a cloning fashion:

fd = open("newfile", O_CREAT|O_RDWR, 0644);
fstat(fd, &st);

printf("new file is %d\n", (int)st.st_ino);

Once you have created a file, you can open() and unlink() it by its returned
inode number retrieved from the stat call, ie:

fd = open("5", O_RDWR);

The creation permissions depend entirely if you have write access to the
root directory of the filesystem.

To get the list of currently allocated inodes, VOP_READDIR has been added
which returns a directory listing of those currently allocated.

--

What this entails:

* patching conf/files and conf/options to include IFS as a new compile
option (and since ifs depends upon FFS, include the FFS routines)

* An entry in i386/conf/NOTES indicating IFS exists and where to go for
an explanation

* Unstaticize a couple of routines in src/sys/ufs/ffs/ which the IFS
routines require (ffs_mount() and ffs_reload())

* a new bunch of routines in src/sys/ufs/ifs/ which implement the IFS
routines. IFS replaces some of the vfsops, and a handful of vnops -
most notably are VFS_VGET(), VOP_LOOKUP(), VOP_UNLINK() and VOP_READDIR().
Any other directory operation is marked as invalid.

What this results in:

* an IFS partition's create permissions are controlled by the perm/ownership of
the root mount point, just like a normal directory

* Each inode has perm and ownership too

* IFS does *NOT* mean an FFS partition can be opened per inode. This is a
completely seperate filesystem here

* Softupdates doesn't work with IFS, and really I don't think it needs it.
Besides, fsck's are FAST. (Try it :-)

* Inodes 0 and 1 aren't allocatable because they are special (dump/swap IIRC).
Inode 2 isn't allocatable since UFS/FFS locks all inodes in the system against
this particular inode, and unravelling THAT code isn't trivial. Therefore,
useful inodes start at 3.

Enjoy, and feedback is definitely appreciated!

This patch corrects the first round of panics and hangs reported
with the new snapshot code.

Update addaliasu to correctly implement the semantics of the old
checkalias function. When a device vnode first comes into existence,
check to see if an anonymous vnode for the same device was created
at boot time by bdevvp(). If so, adopt the bdevvp vnode rather than
creating a new vnode for the device. This corrects a problem which
caused the kernel to panic when taking a snapshot of the root
filesystem.

Change the calling convention of vn_write_suspend_wait() to be the
same as vn_start_write().

Split out softdep_flushworklist() from softdep_flushfiles() so that
it can be used to clear the work queue when suspending filesystem
operations.

Access to buffers becomes recursive so that snapshots can recursively
traverse their indirect blocks using ffs_copyonwrite() when checking
for the need for copy on write when flushing one of their own indirect
blocks. This eliminates a deadlock between the syncer daemon and a
process taking a snapshot.

Ensure that softdep_process_worklist() can never block because of a
snapshot being taken. This eliminates a problem with buffer starvation.

Cleanup change in ffs_sync() which did not synchronously wait when
MNT_WAIT was specified. The result was an unclean filesystem panic
when doing forcible unmount with heavy filesystem I/O in progress.

Return a zero'ed block when reading a block that was not in use at
the time that a snapshot was taken. Normally, these blocks should
never be read. However, the readahead code will occationally read
them which can cause unexpected behavior.

Clean up the debugging code that ensures that no blocks be written
on a filesystem while it is suspended. Snapshots must explicitly
label the blocks that they are writing during the suspension so that
they do not cause a `write on suspended filesystem' panic.

Reorganize ffs_copyonwrite() to eliminate a deadlock and also to
prevent a race condition that would permit the same block to be
copied twice. This change eliminates an unexpected soft updates
inconsistency in fsck caused by the double allocation.

Use bqrelse rather than brelse for buffers that will be needed
soon again by the snapshot code. This improves snapshot performance.

Add snapshots to the fast filesystem. Most of the changes support
the gating of system calls that cause modifications to the underlying
filesystem. The gating can be enabled by any filesystem that needs
to consistently suspend operations by adding the vop_stdgetwritemount
to their set of vnops. Once gating is enabled, the function
vfs_write_suspend stops all new write operations to a filesystem,
allows any filesystem modifying system calls already in progress
to complete, then sync's the filesystem to disk and returns. The
function vfs_write_resume allows the suspended write operations to
begin again. Gating is not added by default for all filesystems as
for SMP systems it adds two extra locks to such critical kernel
paths as the write system call. Thus, gating should only be added
as needed.

Details on the use and current status of snapshots in FFS can be
found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness
is not included here. Unless and until you create a snapshot file,
these changes should have no effect on your system (famous last words).

Clean up warning about undeclared function by declaring softdep_fsync
in mount.h instead of ffs_extern.h. The correct solution is to use
an indirect function pointer so that the kernel does not have to be
built with options FFS, but that will be left for another day.

ARGH! I have too many source trees :-(

Fix prototype errors in last commit.

Make static non-exported functions from soft updates.

We do not have ffs_checkexp, so remove the prototype

Seperate the export check in VFS_FHTOVP, exports are now checked via
VFS_CHECKEXP.

Add fh(open|stat|stafs) syscalls to allow userland to query filesystems
based on (network) filehandle.

Obtained from: NetBSD

$Id$ -> $FreeBSD$

Add a hook to ffs_fsync to allow soft updates to get first chance at doing
a sync on the block device for the filesystem. That allows it to push the
bitmap blocks before the inode blocks which greatly reduces the number of
inode rollbacks that need to be done.

Don't pass unused unused timestamp args to UFS_UPDATE() or waste
time initializing them. This almost finishes centralizing (in-core)
timestamp updates in ufs_itimes().

Forward declare even more structs to restore some self-sufficiency.
Didn't fix new dependence on <ufs/ufs/inode.h> and its prerequisites.

Reviewed by: dyson@freebsd.org (john Dyson), dg@root.com (david greenman)
Submitted by: Kirk McKusick (mcKusick@mckusick.com)
Obtained from: WHistle development tree

Forward declare some structs so that this file is more self-sufficient.

Staticized.

Another VFS cleanup "kilo commit"

1. Remove VOP_UPDATE, it is (also) an UFS/{FFS,LFS,EXT2FS,MFS}
intereface function, and now lives in the ufsmount structure.

2. Remove VOP_SEEK, it was unused.

3. Add mode default vops:

VOP_ADVLOCK vop_einval
VOP_CLOSE vop_null
VOP_FSYNC vop_null
VOP_IOCTL vop_enotty
VOP_MMAP vop_einval
VOP_OPEN vop_null
VOP_PATHCONF vop_einval
VOP_READLINK vop_einval
VOP_REALLOCBLKS vop_eopnotsupp

And remove identical functionality from filesystems

4. Add vop_stdpathconf, which returns the canonical stuff. Use
it in the filesystems. (XXX: It's probably wrong that specfs
and fifofs sets this vop, shouldn't it come from the "host"
filesystem, for instance ufs or cd9660 ?)

5. Try to make system wide VOP functions have vop_* names.

6. Initialize the um_* vectors in LFS.

(Recompile your LKMS!!!)

VFS mega cleanup commit (x/N)

1. Add new file "sys/kern/vfs_default.c" where default actions for
VOPs go. Implement proper defaults for ABORTOP, BWRITE, LEASE,
POLL, REVOKE and STRATEGY. Various stuff spread over the entire
tree belongs here.

2. Change VOP_BLKATOFF to a normal function in cd9660.

3. Kill VOP_BLKATOFF, VOP_TRUNCATE, VOP_VFREE, VOP_VALLOC. These
are private interface functions between UFS and the underlying
storage manager layer (FFS/LFS/MFS/EXT2FS). The functions now
live in struct ufsmount instead.

4. Remove a kludge of VOP_ functions in all filesystems, that did
nothing but obscure the simplicity and break the expandability.
If a filesystem doesn't implement VOP_FOO, it shouldn't have an
entry for it in its vnops table. The system will try to DTRT
if it is not implemented. There are still some cruft left, but
the bulk of it is done.

5. Fix another VCALL in vfs_cache.c (thanks Bruce!)

Add type arg to ffs_mountfs and avoid examining v_tag to find out
if MFS is getting a free ride.

Use generic ufs_reclaim().

Clustered read and write are switched at mount-option level.

1. Clustered I/O is switched by the MNT_NOCLUSTERR and MNT_NOCLUSTERW
bits of the mnt_flag. The sysctl variables, vfs.foo.doclusterread
and vfs.foo.doclusterwrite are deleted. Only mount option can
control clustered I/O from userland.
2. When foofs_mount mounts block device, foofs_mount checks D_CLUSTERR
and D_CLUSTERW bits of the d_flags member in the block device switch
table. If D_NOCLUSTERR / D_NOCLUSTERW are set, MNT_NOCLUSTERR /
MNT_NOCLUSTERW bits will be set. In this case, MNT_NOCLUSTERR and
MNT_NOCLUSTERW cannot be cleared from userland.
3. Vnode driver disables both clustered read and write.
4. Union filesystem disables clutered write.

Reviewed by: bde

Fix all areas of the system (or at least all those in LINT) to avoid storing
socket addresses in mbufs. (Socket buffers are the one exception.) A number
of kernel APIs needed to get fixed in order to make this happen. Also,
fix three protocol families which kept PCBs in mbufs to not malloc them
instead. Delete some old compatibility cruft while we're at it, and add
some new routines in the in_cksum family.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Add function prototypes for most of the new Lite2 functions.
Also made a few of the miscfs routines static to be
consistent. Some modules simply required some additional
#includes to remove -Wall warnings.

This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.

Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Removed bogus _BEGIN_DECLS/_END_DECLS.

Removed unused struct tag declarations in cloned code.

Added or cleaned up idempotency ifdefs.

Import 4.4BSD-Lite2 onto the vendor branch, note that in the kernel, all
files are off the vendor branch, so this should not change anything.

A "U" marker generally means that the file was not changed in between
the 4.4Lite and Lite-2 releases, and does not need a merge. "C" generally
means that there was a change.

Removed vestigial support for the obsolete FIFO option. In ext2fs
it caused null pointer panics for all fifo operations unless FIFO
was defined.

Staticize.

Introduced a type `vop_t' for vnode operation functions and used
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.

The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter. Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.

Added indirect pointer for ffs_getpages, and added external declaration.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) that I didn't notice when I fixed
"all" such warnings before.

More loadable VFS changes:

- Make a number of filesystems work again when they are statically compiled
(blush)

- FIFOs are no longer optional; ``options FIFO'' removed from distributed
config files.

Fix up some sloppy coding practices:

- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.

NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.

Added $Id$

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

BSD 4.4 Lite Kernel Sources