Date: Mon, 13 Dec 2004 13:33:10 +0200 From: Ruslan Ermilov <ru@FreeBSD.org> To: Poul-Henning Kamp <phk@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/ufs/ffs ffs_vfsops.c Message-ID: <20041213113310.GB51149@ip.net.ua> In-Reply-To: <200412121419.iBCEJBg4048788@repoman.freebsd.org> References: <200412121419.iBCEJBg4048788@repoman.freebsd.org>
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[-- Attachment #1 --] On Sun, Dec 12, 2004 at 02:19:11PM +0000, Poul-Henning Kamp wrote: > phk 2004-12-12 14:19:11 UTC > > FreeBSD src repository > > Modified files: > sys/ufs/ffs ffs_vfsops.c > Log: > With the introduction of UFS2 we started looking for superblocks in > four different locations on a prospective filesystem. > > If we found none, we forgot to invalidate the four buffers, thus the > following sequence would fails: > > (md0 = blank disk) > mount /dev/md0 /mnt > (fails, no superblocks) > newfs /dev/md0 > (writes using physio which does not go through buffercache). > mount /dev/md0 /mnt > (still fails, the four cached buffers still contain no superblocks) > > Found by: ru > > Revision Changes Path > 1.263 +1 -0 src/sys/ufs/ffs/ffs_vfsops.c > For some reason, this is only a problem on 6.0-CURRENT. RELENG_5, for example, doesn't exhibit this particular problem. But originally, I had my issue with floppies, attempting to write a newer BIOS on my amd64 box, I needed to create and fill an MS-DOS formatted diskette. Everything was done on i386. First issue: - boot with a blank (unformatted) diskette present in the drive (for testing purposes, "blank" == all zeroes) - newfs_msdos it -- succeeds - mount_msdosfs it -- fails Another issue: - boot without a diskette in the drive - insert a diskette #1 into the drive - newfs_msdos it - mount_msdosfs it - copy some files onto it - unmount it - insert another (possibly unformatted) diskette #2 - mount_msdosfs it and find it somehow succeeds - list the contents of the diskette and find that it's identical to the contents of diskette #1, including MD5 checksums of all files This smells like a bufcache issue, but I may be wrong about it. Cheers, -- Ruslan Ermilov ru@FreeBSD.org FreeBSD committer [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBvX32qRfpzJluFF4RAmvFAJ9sp2gX9j6xAzBXSxA5x3fxTx3mCACfQyAx paZfhG/6MQ0FrSAaV1RLnr8= =ixvP -----END PGP SIGNATURE-----
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