the SF_IMMUTABLE flag to prevent writing. Instead put in explicit
checking for the SF_SNAPSHOT flag in the appropriate places. With
this change, it is now possible to rename and link to snapshot files.
It is also possible to set or clear any of the owner, group, or
other read bits on the file, though none of the write or execute
bits can be set. There is also an explicit test to prevent the
setting or clearing of the SF_SNAPSHOT flag via chflags() or
fchflags(). Note also that the modify time cannot be changed as
it needs to accurately reflect the time that the snapshot was taken.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
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.
attribute data size.
o Fortunately it turned out to be an unused constant left over from an
earlier implementation, and is therefore being removed so as not to
confuse casual observers.
Submitted by: mbendiks@eunet.no
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).
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.
advance preparation for them to get migrated into place so that
subsequent changes in utilities will not fail to compile for lack
of up-to-date header files in /usr/include.
after the acquisition of any advisory locks. This fix corrects a case
in which a process tries to open a file with a non-blocking exclusive
lock. Even if it fails to get the lock it would still truncate the
file even though its open failed. With this change, the truncation
is done only after the lock is successfully acquired.
Obtained from: BSD/OS
the system would panic when a user's inode quota was exceeded (see
PR 18959 for details). This fixes that problem.
PR: 18959
Submitted by: Jason Godsey <jason@unixguy.fidalgo.net>
check to see if it has been committed to disk. If it has never
been written, it can be freed immediately. For short lived files
this change allows the same inode to be reused repeatedly.
Similarly, when upgrading a fragment to a larger size, if it
has never been claimed by an inode on disk, it too can be freed
immediately making it available for reuse often in the next slowly
growing block of the same file.
if an FFS partition returns EOPNOTSUPP, as it just means extended
attributes weren't enabled on that partition. Prevents spurious
warning per-partition at shutdown.
<sys/bio.h>.
<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.
Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.
Still a few bogus uses of struct buf to track down.
Repocopy by: peter
provide locking over extended attribute operations, requiring that
individual operations be atomic. Allowing non-zero starting offsets
permits applications/etc to put themselves at risk for inconsistent
behavior. As VOP_SETEXTATTR already prohibited non-zero write offsets,
this makes sense.
Suggested by: Andreas Gruenbacher <a.gruenbacher@bestbits.at>
reset their grace timer as their ownership crossed the soft limit
threshhold. Thus if they had been over their limit in the past,
they were suddenly penalized as if they had been over their limit
ever since. The fix is to check when root gives away files, that
when the receiving user crosses their soft limit, their grace timer
is reset. See the PR report for a detailed method of reproducing
the bug.
PR: kern/17128
Submitted by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
chances of consistency with other file/directory meta-data in a
write. In the current set of extended attribute applications,
this does not hurt much. This should be discussed again later when
it comes time to optimize performance of attributes.
o Include an inode generation number in the per-attribute header
information. This allows consistency verification to catch when
a crash occurs, or an inode is recycled while attributes are not
properly configured. For now, an irritating error message is
displayed when an inconsistency occurs. At some point, may introduce
an ``extattrctl check ...'' which catches these before attributes
are enabled. Not today. If you get this message, it means you
somehow managed to get your attribute backing file out of synch
with the file system. When this occurs, attribute not found is
returned (== undefined). Writes will overwrite the value there
correcting the problem. Might want to think about introducing
a new errno or two to handle this kind of situation.
Discussed with: kris
o Put back in {} removed during over-zealous cleanup of gratuitous
debugging output during preparation for the commit. Due to the
missing {}, writes on extended attributes always silently failed.
Doh.
o Don't unlock the target vnode if it's the backing vnode, as we
don't lock the target vnode if it's the backing vnode.
Exceptions:
Vinum untouched. This means that it cannot be compiled.
Greg Lehey is on the case.
CCD not converted yet, casts to struct buf (still safe)
atapi-cd casts to struct buf to examine B_PHYS
(name, value) pairs to be associated with inodes. This support is
used for ACLs, MAC labels, and Capabilities in the TrustedBSD
security extensions, which are currently under development.
In this implementation, attributes are backed to data vnodes in the
style of the quota support in FFS. Support for FFS extended
attributes may be enabled using the FFS_EXTATTR kernel option
(disabled by default). Userland utilities and man pages will be
committed in the next batch. VFS interfaces and man pages have
been in the repo since 4.0-RELEASE and are unchanged.
o ufs/ufs/extattr.h: UFS-specific extattr defines
o ufs/ufs/ufs_extattr.c: bulk of support routines
o ufs/{ufs,ffs,mfs}/*.[ch]: hooks and extattr.h includes
o contrib/softupdates/ffs_softdep.c: extattr.h includes
o conf/options, conf/files, i386/conf/LINT: added FFS_EXTATTR
o coda/coda_vfsops.c: XXX required extattr.h due to ufsmount.h
(This should not be the case, and will be fixed in a future commit)
Currently attributes are not supported in MFS. This will be fixed.
Reviewed by: adrian, bp, freebsd-fs, other unthanked souls
Obtained from: TrustedBSD Project
devstat_end_transaction_bio()
bioq_* versions of bufq_* incl bioqdisksort()
the corresponding "buf" versions will disappear when no longer used.
Move b_offset, b_data and b_bcount to struct bio.
Add BIO_FORMAT as a hack for fd.c etc.
We are now largely ready to start converting drivers to use struct
bio instead of struct buf.
(Much of this done by script)
Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.
Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.
Add bio_queue field for struct bio aware disksort.
Address a lot of stylistic issues brought up by bde.
async I/O's. The sequential read heuristic has been extended to
cover writes as well. We continue to call cluster_write() normally,
thus blocks in the file will still be reallocated for large (but still
random) I/O's, but I/O will only be initiated for truely sequential
writes.
This solves a number of annoying situations, especially with DBM (hash
method) writes, and also has the side effect of fixing a number of
(stupid) benchmarks.
Reviewed-by: mckusick
substitute BUF_WRITE(foo) for VOP_BWRITE(foo->b_vp, foo)
substitute BUF_STRATEGY(foo) for VOP_STRATEGY(foo->b_vp, foo)
This patch is machine generated except for the ccd.c and buf.h parts.
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.
B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.
Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.
Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.
This change is a step in the direction towards a stackable BIO capability.
A lot of this patch were machine generated (Thanks to style(9) compliance!)
Vinum users: Greg has not had time to test this yet, be careful.
the unwary if the code were called in slightly different ways.
1) In ufs_bmaparray() the code for calculating 'runb' will stop one block
short of the first entry in an indirect block. i.e. if an indirect block
contains N block numbers b[0]..b[N-1] then the code will never check if
b[0] and b[1] are sequential. For reference, compare with the equivalent
code that deals with direct blocks.
2) In ufs_lookup() there is an off-by-one error in the test that checks
if dp->i_diroff is outside the range of the the current directory size.
This is completely harmless, since the following while-loop condition
'dp->i_offset < endsearch' is never met, so the code immediately
does a second pass starting at dp->i_offset = 0.
3) Again in ufs_lookup(), the condition in a sanity check is wrong
for directories that are longer than one block. This bug means that
the sanity check is only effective for small directories.
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
being accessed after the bp had been releaed. A simple move of the
brelse() solves the problem.
Approved by: jkh
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
filesystem fills up. If the first indirect block exists and FFS is able
to allocate deeper indirect blocks, but is not able to allocate the
data block, FFS improperly unwinds the indirect blocks and leaves a
block pointer hanging to a freed block. This will cause a panic later
when the file is removed. The solution is to properly account for the
first block-pointer-to-an-indirect-block we had to create in a balloc
operation and then unwind it if a failure occurs.
Detective work by: Ian Dowse <iedowse@maths.tcd.ie>
Reviewed by: mckusick, Ian Dowse <iedowse@maths.tcd.ie>
Approved by: jkh
to the current jail/chflags interactions. This fix conditionalizes ``root
behavior'' in the chflags() case on not being in jail, so attempts to
perform a chflags in a jail are limited to what a normal user could do.
For example, this does allow setting of user flags as appropriate, but
prohibits changing of system flags.
Reviewed by: bde
a mess in securelevel environments. Results in one warning during
/etc/rc as it attempts to remove file flags, but this is harmless.
Approved by: High Lord Hubbard
have a write in progress. Otherwise one can get in an infinite loop
trying to get them all flushed.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
set of restrictions for cancelling an inode dependency (inodedep)
is somewhat stronger than originally coded. Since this check appears
in two places, we codify it into the function check_inode_unwritten
which we then call from the two sites, one freeing blocks and the
other freeing directory entries.
Submitted by: Steinar Haug via Matthew Dillon
so that they never try to lock an inode corresponding to ".." as this
can lead to deadlock. We observe that any inode with an updated link count
is always pushed into its buffer at the time of the link count change, so
we do not need to do a VOP_UPDATE, but merely find its buffer and write it.
The only time we need to get the inode itself is from the result of a
mkdir whose name will never be ".." and hence locking such an inode will
never request a lock above us in the filesystem tree. Thanks to Brian
Fundakowski Feldman for providing the test program that tickled soft updates
into hanging in "inode" sleep.
Submitted by: Brian Fundakowski Feldman <green@FreeBSD.org>
to sleep). Locking 101, part 2: do not look at buffer contents after
you have been asleep. There is no telling what wonderous changes may
have occurred.
This seems to be responsible for a bunch of panics where the process
sleeps and something else finds softupdates "locked" when it shouldn't
be. This commit is unreviewed, but has been a big help here.
Previously my boxes would panic pretty much on the first fsync() that
wrote something to disk.
it is no longer sufficient to get a lock on a buffer to know
that its write has been completed. We have to first get the
lock on the buffer, then check to see if it is doing a
background write. If it is doing background write, we have
to wait for the background write to finish, then check to see
if that fullfilled our dependency, and if not to start another
write. Luckily the explanation is longer than the fix.
a vnode has not been written (which would clear certain of its
dependencies). The problems arises because fsync with MNT_NOWAIT
no longer pushes all the dirty blocks associated with a vnode. It
skips those that require rollbacks, since they will just get instantly
dirty again. Such skipped blocks are marked so that they will not be
skipped a second time (otherwise circular dependencies would never
clear). So, we fsync twice to ensure that everything will be written
at least once.
The problem occurs when an indirect block and a data block are
being allocated at the same time. For example when the 13th block
of the file is written, the filesystem needs to allocate the first
indirect block and a data block. If the indirect block allocation
succeeds, but the data block allocation fails, the error code
dellocates the indirect block as it has nothing at which to point.
Unfortunately, it does not deallocate the indirect block's associated
dependencies which then fail when they find the block unexpectedly
gone (ptr == 0 instead of its expected value). The fix is to fsync
the file before doing the block rollback, as the fsync will flush
out all of the dependencies. Once the rollback is done the file
must be fsync'ed again so that the soft updates code does not find
unexpected changes. This approach is much slower than writing the
code to back out the extraneous dependencies, but running out of
disk space is not expected to be a common occurence, so just getting
it right is the main criterion.
PR: kern/15063
Submitted by: Assar Westerlund <assar@stacken.kth.se>
have been cleaned up by deallocte_dependencies(). Once that is done, it
is safe to post the request to free the blocks. A similar change is also
needed for the freefile case.
1) Fastpath deletions. When a file is being deleted, check to see if it
was so recently created that its inode has not yet been written to
disk. If so, the delete can proceed to immediately free the inode.
2) Background writes: No file or block allocations can be done while the
bitmap is being written to disk. To avoid these stalls, the bitmap is
copied to another buffer which is written thus leaving the original
available for futher allocations.
3) Link count tracking. Constantly track the difference in i_effnlink and
i_nlink so that inodes that have had no change other than i_effnlink
need not be written.
4) Identify buffers with rollback dependencies so that the buffer flushing
daemon can choose to skip over them.
of dirrem structure rather than the collaterally created freeblks
and freefile structures. Limit the rate of buffer dirtying by the
syncer process during periods of intense file removal.
check before the inode is unlocked while grabbing its parent directory.
Once it is unlocked, other operations may slip in that could make
the inode-is-flushed check fail. Allowing other writes to the inode
before returning from fsync does not break the semantics of fsync
since we have flushed everything that was dirty at the time of the
fsync call.
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.
when I made the absence of the clean flag sticky in rev.1.88. This
was a problem main for "mount /". There is no way to mount "/" for
writing without using mount -u (normally implicitly), so after
"mount -f /" of an unclean filesystem, the absence of the clean flag
was sticky forever.
quite dangerous, since the process may hold locks at the point,
and if it is stopped in that tsleep the machine may hang. Because
the sleep is so short, the PCATCH is not required here, so it has
been removed. For the future, the FreeBSD team needs to decide
whether it is still reasonable to stop a process in tsleep, as that
may affect any other code that uses PCATCH while holding kernel locks.
Submitted by: Dmitrij Tejblum <tejblum@arc.hq.cti.ru>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* The ASSERT_VOP_(UN)LOCKED family is extended to use what this gives them
* Extend the vnode_if.src format to allow more exact specification than
locked/unlocked.
This commit should not do any semantic changes unless you are using
DEBUG_VFS_LOCKS.
Discussed with: grog, mch, peter, phk
Reviewed by: peter
Add MD_ROOT and MD_ROOT_SIZE options to the md driver.
Make the md driver handle MFS_ROOT and MFS_ROOT_SIZE options for compatibility.
Add md driver to GENERIC, PCCARD and LINT.
This is a cleanup which removes the need for some of the worse hacks in
MFS: We really want to have a rootvnode but MFS on a preloaded image
doesn't really have one. md is a true device, so it is less trouble.
This has been tested with make release, and if people remember to add
the "md" pseudo-device to their kernels, PicoBSD should be just fine
as well. If people have no other use for MFS, it can be removed from
the kernel.
Note: Previous commit to these files (except coda_vnops and devfs_vnops)
that claimed to remove WILLRELE from VOP_RENAME actually removed it from
VOP_MKNOD.
Correctly lock vnodes when calling VOP_OPEN() from filesystem mount code.
Unify spec_open() for bdev and cdev cases.
Remove the disabled bdev specific read/write code.
the soft updates changes: only report the link count to be i_effnlink
in ufs_getattr() for file systems that maintain i_effnlink.
Tested by: Mike Dracopoulos <mdraco@math.uoa.gr>
In order to achieve this, root filesystem mount is moved from
SI_ORDER_FIRST to SI_ORDER_SECOND in the SI_SUB_MOUNT_ROOT sysinit
group. Now, modules which wish to usurp the default root mount
can use SI_ORDER_FIRST.
A compiled-in or preloaded MFS filesystem will become the root
filesystem unless the vfs.root.mountfrom environment variable refers
to a valid bootable device. This will normally only be the case when
the kernel and MFS image have been loaded from a disk which has a
valid /etc/fstab file. In this case, the variable should be manually
overridden in the loader, or the kernel booted with -a. In either
case "mfs:" should be supplied as the new value.
Also fix a typo in one DFLTROOT case that would not have compiled.
Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.
This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.
-----------------------------
The core of the signalling code has been rewritten to operate
on the new sigset_t. No methodological changes have been made.
Most references to a sigset_t object are through macros (see
signalvar.h) to create a level of abstraction and to provide
a basis for further improvements.
The NSIG constant has not been changed to reflect the maximum
number of signals possible. The reason is that it breaks
programs (especially shells) which assume that all signals
have a non-null name in sys_signame. See src/bin/sh/trap.c
for an example. Instead _SIG_MAXSIG has been introduced to
hold the maximum signal possible with the new sigset_t.
struct sigprop has been moved from signalvar.h to kern_sig.c
because a) it is only used there, and b) access must be done
though function sigprop(). The latter because the table doesn't
holds properties for all signals, but only for the first NSIG
signals.
signal.h has been reorganized to make reading easier and to
add the new and/or modified structures. The "old" structures
are moved to signalvar.h to prevent namespace polution.
Especially the coda filesystem suffers from the change, because
it contained lines like (p->p_sigmask == SIGIO), which is easy
to do for integral types, but not for compound types.
NOTE: kdump (and port linux_kdump) must be recompiled.
Thanks to Garrett Wollman and Daniel Eischen for pressing the
importance of changing sigreturn as well.
have been there in the first place. A GENERIC kernel shrinks almost 1k.
Add a slightly different safetybelt under nostop for tty drivers.
Add some missing FreeBSD tags
heuristic to detect sequential operation.
VM-related forced clustering code removed from ufs in preparation for a
commit to vm/vm_fault.c that does it more generally.
Reviewed by: David Greenman <dg@root.com>, Alan Cox <alc@cs.rice.edu>
Rename dev->si_bsize_max to si_iosize_max and set it in spec_open
if the device didn't.
Set vp->v_maxio from dev->si_bsize_max in spec_open rather than
in ufs_bmap.c
warnings caused by the arg having the wrong type (not const enough).
The arg was also wrong (a full name instead of a short one) for calls
from from subr_diskmbr.c and pc98/diskslice_machdep.c.
a quick think and discussion among various people some form of some of
these changes will probably be recommitted.
The reversion requested was requested by dg while discussions proceed.
PHK has indicated that he can live with this, and it has been agreed
that some form of some of these changes may return shortly after further
discussion.
the highly non-recommended option ALLOW_BDEV_ACCESS is used.
(bdev access is evil because you don't get write errors reported.)
Kill si_bsize_best before it kills Matt :-)
Use the specfs routines rather having cloned copies in devfs.
Make the alias list a SLIST.
Drop the "fast recycling" optimization of vnodes (including
the returning of a prexisting but stale vnode from checkalias).
It doesn't buy us anything now that we don't hardlimit
vnodes anymore.
Rename checkalias2() and checkalias() to addalias() and
addaliasu() - which takes dev_t and udev_t arg respectively.
Make the revoke syscalls use vcount() instead of VALIASED.
Remove VALIASED flag, we don't need it now and it is faster
to traverse the much shorter lists than to maintain the
flag.
vfs_mountedon() can check the dev_t directly, all the vnodes
point to the same one.
Print the devicename in specfs/vprint().
Remove a couple of stale LFS vnode flags.
Remove unimplemented/unused LK_DRAINED;
have been maintained, and that is still the default. A new sysctl
variable "vfs.timestamp_precision" can be used to enable higher
levels of precision:
0 = seconds only; nanoseconds zeroed (default).
1 = seconds and nanoseconds, accurate within 1/HZ.
2 = seconds and nanoseconds, truncated to microseconds.
>=3 = seconds and nanoseconds, maximum precision.
Level 1 uses getnanotime(), which is fast but can be wrong by up
to 1/HZ. Level 2 uses microtime(). It might be desirable for
consistency with utimes() and friends, which take timeval structures
rather than timespecs. Level 3 uses nanotime() for the higest
precision.
I benchmarked levels 0, 1, and 3 by copying a 550 MB tree with
"cpio -pdu". There was almost negligible difference in the system
times -- much less than 1%, and less than the variation among
multiple runs at the same level. Bruce Evans dreamed up a torture
test involving 1-byte reads with intervening fstat() calls, but
the cpio test seems more realistic to me.
This feature is currently implemented only for the UFS (FFS and
MFS) filesystems. But I think it should be easy to support it in
the others as well.
An earlier version of this was reviewed by Bruce. He's not to
blame for any breakage I've introduced since then.
Reviewed by: bde (an earlier version of the code)
Introduce BUF_STRATEGY(struct buf *, int flag) macro, and use it throughout.
please see comment in sys/conf.h about the flag argument.
Remove strategy argument from all the diskslice/label/bad144
implementations, it should be found from the dev_t.
Remove bogus and unused strategy1 routines.
Remove open/close arguments from dssize(). Pick them up from dev_t.
Remove unused and unfinished setgeom support from diskslice/label/bad144 code.
Set IN_ACCESS for successful reads of 0 bytes (except for requests to
read 0 bytes). This was broken in rev.1.42.
PR: misc/10148
Don't set IN_ACCESS for requests to read 0 bytes.
Don't set IN_ACCESS for unsuccessful reads.
vnodes referencing this device.
Details:
cdevsw->d_parms has been removed, the specinfo is available
now (== dev_t) and the driver should modify it directly
when applicable, and the only driver doing so, does so:
vn.c. I am not sure the logic in checking for "<" was right
before, and it looks even less so now.
An intial pool of 50 struct specinfo are depleted during
early boot, after that malloc had better work. It is
likely that fewer than 50 would do.
Hashing is done from udev_t to dev_t with a prime number
remainder hash, experiments show no better hash available
for decent cost (MD5 is only marginally better) The prime
number used should not be close to a power of two, we use
83 for now.
Add new checkalias2() to get around the loss of info from
dev2udev() in bdevvp();
The aliased vnodes are hung on a list straight of the dev_t,
and speclisth[SPECSZ] is unused. The sharing of struct
specinfo means that the v_specnext moves into the vnode
which grows by 4 bytes.
Don't use a VBLK dev_t which doesn't make sense in MFS, now
we hang a dummy cdevsw on B/Cmaj 253 so that things look sane.
Storage overhead from all of this is O(50k).
Bump __FreeBSD_version to 400009
The next step will add the stuff needed so device-drivers can start to
hang things from struct specinfo
been set for a mount point. Insert missing checks to ensure that all
write operations are done asynchronously when the MNT_ASYNC option
has been requested.
Submitted by: Craig A Soules <soules+@andrew.cmu.edu>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
large (1G) memory machine configurations. I was able to run 'dbench 32'
on a 32MB system without bring the machine to a grinding halt.
* buffer cache hash table now dynamically allocated. This will
have no effect on memory consumption for smaller systems and
will help scale the buffer cache for larger systems.
* minor enhancement to pmap_clearbit(). I noticed that
all the calls to it used constant arguments. Making
it an inline allows the constants to propogate to
deeper inlines and should produce better code.
* removal of inherent vfs_ioopt support through the emplacement
of appropriate #ifdef's, with John's permission. If we do not
find a use for it by the end of the year we will remove it entirely.
* removal of getnewbufloops* counters & sysctl's - no longer
necessary for debugging, getnewbuf() is now optimal.
* buffer hash table functions removed from sys/buf.h and localized
to vfs_bio.c
* VFS_BIO_NEED_DIRTYFLUSH flag and support code added
( bwillwrite() ), allowing processes to block when too many dirty
buffers are present in the system.
* removal of a softdep test in bdwrite() that is no longer necessary
now that bdwrite() no longer attempts to flush dirty buffers.
* slight optimization added to bqrelse() - there is no reason
to test for available buffer space on B_DELWRI buffers.
* addition of reverse-scanning code to vfs_bio_awrite().
vfs_bio_awrite() will attempt to locate clusterable areas
in both the forward and reverse direction relative to the
offset of the buffer passed to it. This will probably not
make much of a difference now, but I believe we will start
to rely on it heavily in the future if we decide to shift
some of the burden of the clustering closer to the actual
I/O initiation.
* Removal of the newbufcnt and lastnewbuf counters that Kirk
added. They do not fix any race conditions that haven't already
been fixed by the gbincore() test done after the only call
to getnewbuf(). getnewbuf() is a static, so there is no chance
of it being misused by other modules. ( Unless Kirk can think
of a specific thing that this code fixes. I went through it
very carefully and didn't see anything ).
* removal of VOP_ISLOCKED() check in flushbufqueues(). I do not
think this check is necessary, the buffer should flush properly
whether the vnode is locked or not. ( yes? ).
* removal of extra arguments passed to getnewbuf() that are not
necessary.
* missed cluster_wbuild() that had to be a cluster_wbuild_wb() in
vfs_cluster.c
* vn_write() now calls bwillwrite() *PRIOR* to locking the vnode,
which should greatly aid flushing operations in heavy load
situations - both the pageout and update daemons will be able
to operate more efficiently.
* removal of b_usecount. We may add it back in later but for now
it is useless. Prior implementations of the buffer cache never
had enough buffers for it to be useful, and current implementations
which make more buffers available might not benefit relative to
the amount of sophistication required to implement a b_usecount.
Straight LRU should work just as well, especially when most things
are VMIO backed. I expect that (even though John will not like
this assumption) directories will become VMIO backed some point soon.
Submitted by: Matthew Dillon <dillon@backplane.com>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
The cdevsw_add() function now finds the major number(s) in the
struct cdevsw passed to it. cdevsw_add_generic() is no longer
needed, cdevsw_add() does the same thing.
cdevsw_add() will print an message if the d_maj field looks bogus.
Remove nblkdev and nchrdev variables. Most places they were used
bogusly. Instead check a dev_t for validity by seeing if devsw()
or bdevsw() returns NULL.
Move bdevsw() and devsw() functions to kern/kern_conf.c
Bump __FreeBSD_version to 400006
This commit removes:
72 bogus makedev() calls
26 bogus SYSINIT functions
if_xe.c bogusly accessed cdevsw[], author/maintainer please fix.
I4b and vinum not changed. Patches emailed to authors. LINT
probably broken until they catch up.
- Fix an error message.
- Do the MFS_ROOT setting of mountrootfsname in mfs_init() instead of
cpu_rootconf().
- Set rootdev in mfs_init instead of later in mfs_mount() iff MFS_ROOT.
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.
udev_t in the kernel but still called dev_t in userland.
Provide functions to manipulate both types:
major() umajor()
minor() uminor()
makedev() umakedev()
dev2udev() udev2dev()
For now they're functions, they will become in-line functions
after one of the next two steps in this process.
Return major/minor/makedev to macro-hood for userland.
Register a name in cdevsw[] for the "filedescriptor" driver.
In the kernel the udev_t appears in places where we have the
major/minor number combination, (ie: a potential device: we
may not have the driver nor the device), like in inodes, vattr,
cdevsw registration and so on, whereas the dev_t appears where
we carry around a reference to a actual device.
In the future the cdevsw and the aliased-from vnode will be hung
directly from the dev_t, along with up to two softc pointers for
the device driver and a few houskeeping bits. This will essentially
replace the current "alias" check code (same buck, bigger bang).
A little stunt has been provided to try to catch places where the
wrong type is being used (dev_t vs udev_t), if you see something
not working, #undef DEVT_FASCIST in kern/kern_conf.c and see if
it makes a difference. If it does, please try to track it down
(many hands make light work) or at least try to reproduce it
as simply as possible, and describe how to do that.
Without DEVT_FASCIST I belive this patch is a no-op.
Stylistic/posixoid comments about the userland view of the <sys/*.h>
files welcome now, from userland they now contain the end result.
Next planned step: make all dev_t's refer to the same devsw[] which
means convert BLK's to CHR's at the perimeter of the vnodes and
other places where they enter the game (bootdev, mknod, sysctl).
Made a new (inline) function devsw(dev_t dev) and substituted it.
Changed to the BDEV variant to this format as well: bdevsw(dev_t dev)
DEVFS will eventually benefit from this change too.
Virtualize bdevsw[] from cdevsw. bdevsw() is now an (inline)
function.
Join CDEV_MODULE and BDEV_MODULE to DEV_MODULE (please pay attention
to the order of the cmaj/bmaj arguments!)
Join CDEV_DRIVER_MODULE and BDEV_DRIVER_MODULE to DEV_DRIVER_MODULE
(ditto!)
(Next step will be to convert all bdev dev_t's to cdev dev_t's
before they get to do any damage^H^H^H^H^H^Hwork in the kernel.)
files at once on a filesystem running soft updates. The root of
the problem is that soft updates limits the amount of memory that
may be allocated to dependency structures so as to avoid hogging
kernel memory. The original algorithm just waited for the disk I/O
to catch up and reduce the number of dependencies. This new code
takes a much more aggressive approach. Basically there are two
resources that routinely hit the limit. Inode dependencies during
periods with a high file creation rate and file and block removal
dependencies during periods with a high file removal rate. I have
attacked these problems from two fronts. When the inode dependency
limits are reached, I pick a random inode dependency, UFS_UPDATE
it together with all the other dirty inodes contained within its
disk block and then write that disk block. This trick usually
clears 5-50 inode dependencies in a single disk I/O. For block and
file removal dependencies, I pick a random directory page that has
at least one remove pending and VOP_FSYNC its directory. That
releases all its removal dependencies to the work queue. To further
hasten things along, I also immediately start the work queue process
rather than waiting for its next one second scheduled run.
piecemeal, middle-of-file writes for NFS. These hacks have caused no
end of trouble, especially when combined with mmap(). I've removed
them. Instead, NFS will issue a read-before-write to fully
instantiate the struct buf containing the write. NFS does, however,
optimize piecemeal appends to files. For most common file operations,
you will not notice the difference. The sole remaining fragment in
the VFS/BIO system is b_dirtyoff/end, which NFS uses to avoid cache
coherency issues with read-merge-write style operations. NFS also
optimizes the write-covers-entire-buffer case by avoiding the
read-before-write. There is quite a bit of room for further
optimization in these areas.
The VM system marks pages fully-valid (AKA vm_page_t->valid =
VM_PAGE_BITS_ALL) in several places, most noteably in vm_fault. This
is not correct operation. The vm_pager_get_pages() code is now
responsible for marking VM pages all-valid. A number of VM helper
routines have been added to aid in zeroing-out the invalid portions of
a VM page prior to the page being marked all-valid. This operation is
necessary to properly support mmap(). The zeroing occurs most often
when dealing with file-EOF situations. Several bugs have been fixed
in the NFS subsystem, including bits handling file and directory EOF
situations and buf->b_flags consistancy issues relating to clearing
B_ERROR & B_INVAL, and handling B_DONE.
getblk() and allocbuf() have been rewritten. B_CACHE operation is now
formally defined in comments and more straightforward in
implementation. B_CACHE for VMIO buffers is based on the validity of
the backing store. B_CACHE for non-VMIO buffers is based simply on
whether the buffer is B_INVAL or not (B_CACHE set if B_INVAL clear,
and vise-versa). biodone() is now responsible for setting B_CACHE
when a successful read completes. B_CACHE is also set when a bdwrite()
is initiated and when a bwrite() is initiated. VFS VOP_BWRITE
routines (there are only two - nfs_bwrite() and bwrite()) are now
expected to set B_CACHE. This means that bowrite() and bawrite() also
set B_CACHE indirectly.
There are a number of places in the code which were previously using
buf->b_bufsize (which is DEV_BSIZE aligned) when they should have
been using buf->b_bcount. These have been fixed. getblk() now clears
B_DONE on return because the rest of the system is so bad about
dealing with B_DONE.
Major fixes to NFS/TCP have been made. A server-side bug could cause
requests to be lost by the server due to nfs_realign() overwriting
other rpc's in the same TCP mbuf chain. The server's kernel must be
recompiled to get the benefit of the fixes.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
unallocated parts of the last page when the file ended on a frag
but not a page boundary.
Delimitted by tags PRE_MATT_MMAP_EOF and POST_MATT_MMAP_EOF,
in files alpha/alpha/pmap.c i386/i386/pmap.c nfs/nfs_bio.c vm/pmap.h
vm/vm_page.c vm/vm_page.h vm/vnode_pager.c miscfs/specfs/spec_vnops.c
ufs/ufs/ufs_readwrite.c kern/vfs_bio.c
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Alan Cox <alc@freebsd.org>
in my tree for 12+ months, and I just noticed that NetBSD have (I think,
I've just seen the commit, not the change) just zapped it there.
It wasn't in the options files or LINT either.
include of <sys/queue.h> in the !KERNEL case. The prerequisites
for <ufs/ufs/quota.h> were broken in Lite2 by converting some of
the kernel declarations to use queue macros without including
<sys/queue.h>. <sys/queue.h> was included in applications in
/usr/src instead. We polluted this file instead of merging the
changes in the applications.
Include <sys/queue.h> in the KERNEL case, and forward-declare all
structs that are used in prototypes, so that this file is almost
self-sufficient even in the kernel.
Obtained from: mostly from NetBSD
so that non-sloppy applications can call it without using disgusting
casts to avoid warnings. The 4th arg is sort of varargs -- it must
sometimes represent a filename, sometimes a struct pointer, and is
sometimes unused. The arg type is still caddr_t in the kernel.
Obtained from: mostly from NetBSD
lives in ext2_vnops.c for ext2fs. Also remove cast from comparision.
Bruce pointed out that it was bogus since we'd force a signed
comparision when we really wanted an unsigned comparison.
to write all the dirty blocks. If some of those blocks have dependencies,
they will be remarked dirty when the I/O completes. On systems with
really fast I/O systems, it is possible to get in an infinite loop trying
to flush the buffers, because the I/O finishes before we can get all the
dirty buffers off the v_dirtyblkhd list and into the I/O queue. (The
previous algorithm looped over the v_dirtyblkhd list writing out buffers
until the list emptied.) So, now we mark each buffer that we try to
write so that we can distinguish the ones that are being remarked dirty
from those that we have not yet tried to flush. Once we have tried to
push every buffer once, we then push any associated metadata that is
causing the remaining buffers to be redirtied.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
Specifically, the test was in the wrong place, lacked a cast, didn't
unlock the node, and exited to bad rather than abortit. Now we don't
allow renaming of a file with LINK_MAX references. Move the test to
earlier in the code as it is closer to where ip is obtained, as that
is the style of the rest of the function.
Didn't fix the problems bruce pointed out in the rename man page to
include EMLINK, nor address his complaints about how the whole idea of
incrementing the link count during a rename is potentially asking for
trouble.
Also didn't try to correct potential problem Terry pointed out with
decrements not being similarly protected against underflow.
turns out to not be useful to unwind the dependencies and continue in
the face of a fatal error.
Also changed the log() to a printf() in softdep_error() so that it will
be output in the case of a impending panic.
Submitted by: Kirk McKusick <mckusick@mckusick.com>
changes to the VM system to support the new swapper, VM bug
fixes, several VM optimizations, and some additional revamping of the
VM code. The specific bug fixes will be documented with additional
forced commits. This commit is somewhat rough in regards to code
cleanup issues.
Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
MNT_WAIT when we mean boolean `true' or check for that value not being
passed. There was no problem in practice because MNT_WAIT had the
magic value of 1.
I/O requests must be marked P_SYSTEM because if it isn't and the system
decides to swap it or (god forbid) kill it, the system stands a good
chance of locking up.
