Date: Thu, 19 Apr 2001 12:33:13 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: John Baldwin <jhb@FreeBSD.ORG> Cc: Mike Bristow <mike@urgle.com>, hackers@FreeBSD.ORG, Jeremiah Gowdy <data@dualcpus.com> Subject: Re: OpenBSD's FFS/dirpref/softupdates improvements Message-ID: <200104191933.f3JJXDG58095@earth.backplane.com> References: <XFMail.010419101350.jhb@FreeBSD.org>
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I've accepted the job of MFCing the dirpref stuff to -stable ... after
the 4.3 release.
If fsck is clobbering consistently we can probably make the kernel
avoid a panic. I'll look at the issue carefully when I do the MFC.
-Matt
:On 19-Apr-01 Mike Bristow wrote:
:> On Thu, Apr 19, 2001 at 08:57:37AM -0700, Jeremiah Gowdy wrote:
:>> "Two aspects of the FFS filesystem in OpenBSD have received significant
:>> improvements since 2.8, increasing performance dramatically. Thanks to art,
:>> gluk, csapuntz, and a host of other developers and testers, Soft Updates are
:>> now much more stable than ever before. The second improvement, contributed
:>> by gluk@openbsd.org, is a new directory allocation policy (codenamed
:>> "dirpref"). Coupled with soft updates, the new dirpref code offers up to a
:>> 60x speed increase in gluk's tests, documented here:"
:>>
:>> http://groups.google.com/groups?q=dirpref&num=100&hl=en&lr=&safe=off&rnum=2&;
:>> seld=905073910&ic=1
:>>
:>> Does anyone know anything about this ?
:>
:> Commited to -current about 10 April.
:>
:> I suspect that Jordan would shoot someone who suggested a MFC before
:> 4.3 is out.
:
:It needs more work, too. If you try to use an old fsck with the new kernel,
:then the old fsck will clobber some new variables in the superblock. Then the
:new kernel will panic later on instead of doing a sanity check on the new
:values in the superblock and falling back to defaults if they are bogus. This
:is a major POLA bug and the changes shouldn't go into 4.x unless this is fixed.
:This breaks the recommended method of updating stable by doing the installworld
:after rebooting into a new kernel.
:
:--
:
:John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
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