Date: Sun, 28 May 2006 10:23:38 +0400 From: Yar Tikhiy <yar@comp.chem.msu.su> To: Julian Elischer <julian@elischer.org> Cc: freebsd-current@freebsd.org Subject: Re: Root FS corruption Message-ID: <20060528062338.GC74300@comp.chem.msu.su> In-Reply-To: <4479386B.6030008@elischer.org> References: <20060518151232.GA37743@comp.chem.msu.su> <200605181819.k4IIJHL7001150@hardy.tmseck.homedns.org> <20060519085408.GB51604@comp.chem.msu.su> <20060521102204.GB78879@comp.chem.msu.su> <20060526072458.GA47499@comp.chem.msu.su> <20060527110415.GA63440@comp.chem.msu.su> <4479386B.6030008@elischer.org>
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On Sat, May 27, 2006 at 10:43:07PM -0700, Julian Elischer wrote: > Yar Tikhiy wrote: > > > >Folks, I have good news for all of us: This kind of corruption > >isn't done by the kernel. Thanks to Ian Dowse, I found out that > >/boot/loader would rewrite nextboot.conf through libufs or whatever. > >This is done in support.4th, the word is rewrite_nextboot_file. > >Initially I missed a clear sign of the problem being caused by the > >loader: The corrupted data started with `nextboot_enable="NO" \n', > >which is the string written from support.4th. The actual bug must > >be hiding in libufs, or whatever loader uses to access UFS. > > > >Recent technical details of my investigation have been filed > >in PR bin/98005: > > > > http://www.freebsd.org/cgi/query-pr.cgi?pr=98005 > > > >The conclusion is: Avoid nextboot(8) for now. > > the current nextboot fails to provide all the designed functionality > of the previous nextboot. (which is why we still use the old one at > ironport) > One day I'll get around to reimplementing the old one.. > > (the design criteria were:) > > Store the nextboot info "not in a filesystem". (the filesystem may be > corrupt > or there ma be several types of filesystem available). > Change that info from boot0 without writing to a filesystem. > (to note that it was used) > Be able to store different stuff on different disks at the same time. > Be able to ensure that you could specify how many times the > information was used before falling back to something else. The present problem seems to lurk in the BIOS disk access mini-library used by the /sys/boot code, while nextboot just triggers it. Ian Dowse sent me a patch to test. I hope that the fixed library will facilitate your efforts on implementing the new nextboot. Thanks! -- Yar
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