Commit Graph

106 Commits

Author SHA1 Message Date
Matthew Dillon
936524aa02 Implement a low-memory deadlock solution.
Removed most of the hacks that were trying to deal with low-memory
    situations prior to now.

    The new code is based on the concept that I/O must be able to function in
    a low memory situation.  All major modules related to I/O (except
    networking) have been adjusted to allow allocation out of the system
    reserve memory pool.  These modules now detect a low memory situation but
    rather then block they instead continue to operate, then return resources
    to the memory pool instead of cache them or leave them wired.

    Code has been added to stall in a low-memory situation prior to a vnode
    being locked.

    Thus situations where a process blocks in a low-memory condition while
    holding a locked vnode have been reduced to near nothing.  Not only will
    I/O continue to operate, but many prior deadlock conditions simply no
    longer exist.

Implement a number of VFS/BIO fixes

	(found by Ian): in biodone(), bogus-page replacement code, the loop
        was not properly incrementing loop variables prior to a continue
        statement.  We do not believe this code can be hit anyway but we
        aren't taking any chances.  We'll turn the whole section into a
        panic (as it already is in brelse()) after the release is rolled.

	In biodone(), the foff calculation was incorrectly
        clamped to the iosize, causing the wrong foff to be calculated
        for pages in the case of an I/O error or biodone() called without
        initiating I/O.  The problem always caused a panic before.  Now it
        doesn't.  The problem is mainly an issue with NFS.

	Fixed casts for ~PAGE_MASK.  This code worked properly before only
        because the calculations use signed arithmatic.  Better to properly
        extend PAGE_MASK first before inverting it for the 64 bit masking
        op.

	In brelse(), the bogus_page fixup code was improperly throwing
        away the original contents of 'm' when it did the j-loop to
        fix the bogus pages.  The result was that it would potentially
        invalidate parts of the *WRONG* page(!), leading to corruption.

	There may still be cases where a background bitmap write is
        being duplicated, causing potential corruption.  We have identified
        a potentially serious bug related to this but the fix is still TBD.
        So instead this patch contains a KASSERT to detect the problem
  	and panic the machine rather then continue to corrupt the filesystem.
	The problem does not occur very often..  it is very hard to
	reproduce, and it may or may not be the cause of the corruption
	people have reported.

Review by: (VFS/BIO: mckusick, Ian Dowse <iedowse@maths.tcd.ie>)
Testing by: (VM/Deadlock) Paul Saab <ps@yahoo-inc.com>
2000-11-18 23:06:26 +00:00
Poul-Henning Kamp
1d7e3e42e7 Take VBLK devices further out of their missery.
This should fix the panic I introduced in my previous commit on this topic.
2000-11-02 21:14:13 +00:00
John Baldwin
35e0e5b311 Catch up to moving headers:
- machine/ipl.h -> sys/ipl.h
- machine/mutex.h -> sys/mutex.h
2000-10-20 07:58:15 +00:00
Jason Evans
a18b1f1d4d Convert lockmgr locks from using simple locks to using mutexes.
Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is no
longer needed.
2000-10-04 01:29:17 +00:00
Robert Watson
100d2c187c o Introduce vn_extattr_rm(), a helper function in the style of
vn_extattr_get() and vn_extattr_set().  vn_extattr_rm() removes the
  specified extended attribute from a vnode, authorizing the change as
  the kernel (NULL cred).

Obtained from:	TrustedBSD Project
2000-09-22 22:33:13 +00:00
Robert Watson
e81c5f4307 o vn_extattr_set() will now call appropriate vn_start_write() and
vn_finished_write() if IO_NODELOCKED is not set.

Obtained from:	TrustedBSD Project
2000-09-05 03:15:02 +00:00
Robert Watson
e6a9ab52db o Introduce vn_extattr_{get,set}, wrapper routines for VOP_GETEXTATTR
and VOP_SETEXTATTR to simplify calling from in-kernel consumers,
  such as capability code.  Both accept a vnode (optionally locked,
  with ioflg to indicate that), attribute name, and a buffer + buffer
  length in UIO_SYSSPACE.  Both authorize the call as a kernel request,
  with cred set to NULL for the actual VOP_ calls.

Obtained from:	TrustedBSD Project
2000-08-08 17:15:32 +00:00
Kirk McKusick
9b97113391 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.
2000-07-24 05:28:33 +00:00
Kirk McKusick
f2a2857bb3 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).
2000-07-11 22:07:57 +00:00
Kirk McKusick
e6796b67d9 Move the truncation code out of vn_open and into the open system call
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
2000-07-04 03:34:11 +00:00
Jonathan Lemon
cb5ad9d362 Fix stupid braino in last commit, initialize `vp' before we test vp->v_tag.
Spotted by: dillon
2000-06-25 18:10:45 +00:00
Jonathan Lemon
c8bea19ee3 Add a hack to fail registration of kq events on a non-ufs filesystem, as
support for those is non-existent at the moment.
2000-06-22 18:41:07 +00:00
Jake Burkholder
e39756439c Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by:		msmith and others
2000-05-26 02:09:24 +00:00
Jake Burkholder
740a1973a6 Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by:	phk
Reviewed by:	phk
Approved by:	mdodd
2000-05-23 20:41:01 +00:00
Jeroen Ruigrok van der Werven
37d90a44af Fix comment typo.
Submitted by:	nrahlstr
2000-05-12 16:06:49 +00:00
Poul-Henning Kamp
9626b608de Separate the struct bio related stuff out of <sys/buf.h> into
<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
2000-05-05 09:59:14 +00:00
Poul-Henning Kamp
2c9b67a8df Remove unneeded #include <vm/vm_zone.h>
Generated by:	src/tools/tools/kerninclude
2000-04-30 18:52:11 +00:00
Jonathan Lemon
cb679c385e Introduce kqueue() and kevent(), a kernel event notification facility. 2000-04-16 18:53:38 +00:00
Matthew Dillon
e4649cfac3 Change the write-behind code to take more care when starting
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
2000-04-02 00:55:28 +00:00
Poul-Henning Kamp
ba4ad1fcea Give vn_isdisk() a second argument where it can return a suitable errno.
Suggested by:	bde
2000-01-10 12:04:27 +00:00
Kirk McKusick
bd5f5da94d Add bwillwrite to all system calls that create things in the filesystem.
Benchmarks that create huge trees of empty files overwhelm the buffer cache.
2000-01-10 00:08:53 +00:00
Eivind Eklund
762e6b856c Introduce NDFREE (and remove VOP_ABORTOP) 1999-12-15 23:02:35 +00:00
Matthew Dillon
91921bd597 Ensure that garbage from the kernel stack does not wind up being
returned to user mode in the spare fields of the stat structure.

PR:		kern/14966
Reviewed by:	dillon@freebsd.org
Submitted by:	Kelly Yancey kbyanc@posi.net
1999-11-18 08:14:20 +00:00
Peter Wemm
b127fae405 Add a vnode fo_stat() entry point. 1999-11-08 03:32:15 +00:00
Brian Feldman
13ccadd4b0 This is what was "fdfix2.patch," a fix for fd sharing. It's pretty
far-reaching in fd-land, so you'll want to consult the code for
changes.  The biggest change is that now, you don't use
	fp->f_ops->fo_foo(fp, bar)
but instead
	fo_foo(fp, bar),
which increments and decrements the fp refcount upon entry and exit.
Two new calls, fhold() and fdrop(), are provided.  Each does what it
seems like it should, and if fdrop() brings the refcount to zero, the
fd is freed as well.

Thanks to peter ("to hell with it, it looks ok to me.") for his review.
Thanks to msmith for keeping me from putting locks everywhere :)

Reviewed by:	peter
1999-09-19 17:00:25 +00:00
Julian Elischer
85a219d201 Changes to centralise the default blocksize behaviour.
More likely to follow.

Submitted by: phk@freebsd.org
1999-09-09 19:08:44 +00:00
Julian Elischer
7012bab988 Revert a bunch of contraversial changes by PHK. After
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.
1999-09-03 05:16:59 +00:00
Poul-Henning Kamp
de5f40afa6 Improve the returned values in st_blksize a little bit, avoid
accessing union fields not valid for dev_t type.
1999-09-01 05:36:55 +00:00
Poul-Henning Kamp
02e1576966 Make bdev userland access work like cdev userland access unless
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.
1999-08-30 07:56:23 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Brian Feldman
b5fca1cb2a Add FIODTYPE ioctl for getting d_flags (type) info on a device.
Okayed by:	phk
1999-08-27 16:35:37 +00:00
Poul-Henning Kamp
a431597b25 Add a couple of missing but unimportant break; statements. 1999-08-25 11:44:11 +00:00
Poul-Henning Kamp
0232a25188 oops: Add missing include. 1999-08-13 11:22:48 +00:00
Poul-Henning Kamp
3a965c0db0 Move the special-casing of stat(2)->st_blksize for device files
from UFS to the generic level.  For chr/blk devices we don't care
about the blocksize of the filesystem, we want what the device
asked for.
1999-08-13 10:56:07 +00:00
Brian Feldman
e32c66c539 Fix fd race conditions (during shared fd table usage.) Badfileops is
now used in f_ops in place of NULL, and modifications to the files
are more carefully ordered. f_ops should also be set to &badfileops
upon "close" of a file.

This does not fix other problems mentioned in this PR than the first
one.

PR:		11629
Reviewed by:	peter
1999-08-04 18:53:50 +00:00
Alan Cox
6745299365 Add sysctl and support code to allow directories to be VMIO'd. The default
setting for the sysctl is OFF, which is the historical operation.

Submitted by:	dillon
1999-07-26 06:25:53 +00:00
Kirk McKusick
ad8ac923fa These changes appear to give us benefits with both small (32MB) and
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>
1999-07-08 06:06:00 +00:00
Poul-Henning Kamp
8947a90a90 Make sure that stat(2) and friends always return a valid st_dev field.
Pseudo-FS need not fill in the va_fsid anymore, the syscall code
will use the first half of the fsid, which now looks like a udev_t
with major 255.
1999-07-02 16:29:47 +00:00
Poul-Henning Kamp
75c1354190 This Implements the mumbled about "Jail" feature.
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/
1999-04-28 11:38:52 +00:00
Poul-Henning Kamp
f711d546d2 Suser() simplification:
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.
1999-04-27 11:18:52 +00:00
Alan Cox
f78fd73fa6 Address several problems in vn_read and vn_write:
1. Make read-ahead work for pread and aio_read.

2. Fix one place where a comparison of uio_offset with -1
   wasn't updated to use FOF_OFFSET.

3. Honor O_APPEND in the FOF_OFFSET case.

In addition, use the variable name "ioflag" in both vn_read and
vn_write to avoid possible confusion between the variable "flag"
and the parameter "flags".

Submitted by:	Bruce Evans <bde@zeta.org.au> and me
1999-04-21 05:56:45 +00:00
Dmitrij Tejblum
8fe387ab84 Add standard padding argument to pread and pwrite syscall. That should make them
NetBSD compatible.

Add parameter to fo_read and fo_write. (The only flag FOF_OFFSET mean that
the offset is set in the struct uio).

Factor out some common code from read/pread/write/pwrite syscalls.
1999-04-04 21:41:28 +00:00
Alan Cox
cde9bc877b Changed vn_read/write such that fp->f_offset isn't touched
if uio->uio_offset != -1.  This fixes a problem with aio_read/write
and permits a straightforward implementation of pread/pwrite.

PR:		kern/8669
Submitted by:	John Plevyak <jplevyak@inktomi.com>
Reviewed by:	Matthew Dillon <dillon@apollo.backplane.com>
1999-03-26 20:25:21 +00:00
Poul-Henning Kamp
57c90d6fcd Use suser() to determine super-user-ness, don't examine cr_uid directly. 1999-01-30 12:21:49 +00:00
Eivind Eklund
15a1057c46 Add 'options DEBUG_LOCKS', which stores extra information in struct
lock, and add some macros and function parameters to make sure that
the information get to the point where it can be put in the lock
structure.

While I'm here, add DEBUG_VFS_LOCKS to LINT.
1999-01-20 14:49:12 +00:00
Eivind Eklund
fb1167777a Remove the 'waslocked' parameter to vfs_object_create(). 1999-01-05 18:50:03 +00:00
Peter Wemm
f3d6ee090e Only do one VOP_ACCESS() per open() instead of two. This should reduce
the NFSv3 ACCESS RPC problems a little for busy clients that do a lot of
open/close.  The nfs code could probably cache the results, but I'm not
sure whether this would be legal or useful.  The problem is that with
a CPU farm, on each open there would be a lookup, getattr then access RPC
then the read/write RPC activity.  Caching the access results probably
isn't going to help much if the clients access lots of files.  Having the
nfs_access() routine interpret the getattr results is a bit of a hack, but
it's how NFSv2 is done and it might be OK for a mount attribute for v3.
1998-11-02 02:36:16 +00:00
Poul-Henning Kamp
c259b8dd2b Report the mode as the result of the VOP_GETATTR rather than the
vnodes type, they may not correspond.
1998-06-27 06:43:09 +00:00
Doug Rabson
ecbb00a262 This commit fixes various 64bit portability problems required for
FreeBSD/alpha.  The most significant item is to change the command
argument to ioctl functions from int to u_long.  This change brings us
inline with various other BSD versions.  Driver writers may like to
use (__FreeBSD_version == 300003) to detect this change.

The prototype FreeBSD/alpha machdep will follow in a couple of days
time.
1998-06-07 17:13:14 +00:00
Mike Smith
7be2d30077 In the words of the submitter:
---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it.  This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.

Quality testing was done with testvn, and lat_fs from the lmbench suite.

Some NFS client testing courtesy of Patrik Kudo.

vop_mknod and vop_symlink still release the returned vpp.  vop_rename
still releases 4 vnode arguments before it returns.  These remaining cases
will be corrected in the next set of patches.
---------

Submitted by:	Michael Hancock <michaelh@cet.co.jp>
1998-05-07 04:58:58 +00:00