Date: Fri, 5 May 2006 15:42:39 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: David Kirchner <dpk@dpk.net> Cc: stable@freebsd.org, Robert Watson <rwatson@freebsd.org>, Kris Kennaway <kris@obsecurity.org> Subject: Re: quota deadlock on 6.1-RC1 Message-ID: <20060505124239.GG35756@deviant.kiev.zoral.com.ua> In-Reply-To: <35c231bf0605041659m2d90e50y9026f18af592f9f5@mail.gmail.com> References: <44579EE1.6010300@rogers.com> <20060502180557.GA91762@xor.obsecurity.org> <4457A02C.9040408@rogers.com> <20060502182302.GA92027@xor.obsecurity.org> <20060503110503.O58458@fledge.watson.org> <35c231bf0605031821s582b6d03j3ee9d434a596f62a@mail.gmail.com> <20060504014241.GA38346@xor.obsecurity.org> <35c231bf0605032005n4fe38769v9637a9393efb791a@mail.gmail.com> <20060504100110.P17611@fledge.watson.org> <35c231bf0605041659m2d90e50y9026f18af592f9f5@mail.gmail.com>
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--ewQ5hdP4CtoTt3oD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 04, 2006 at 04:59:33PM -0700, David Kirchner wrote: > Here's how to reproduce the snapshot deadlock I'm seeing, with 6.1-RC2 > cvsup'd as of 5 or 6 hours ago: >=20 > 1) dd if=3D/dev/zero of=3D/usr/bigfile bs=3D1024 seek=3D209715200 count= =3D0 > 2) mdconfig -a -t vnode -f /usr/bigfile > 3) bsdlabel -w md0 auto > 4) newfs -U md0a > 5) fsck -v /dev/md0a # ^C this after a second or so, this makes the FS di= rty > 6) mount /dev/md0a /mnt > 7) fsck -v -B /dev/md0a >=20 > in another window: > 8) while true; do ls -al /mnt/.snap;sleep 1;done >=20 > It locks up every time for me, with no further disk activity. > Unfortunately, for some reason, my server console became unaccessable, > so I'm not able to get to the kdb prompt. If I can get to it later, > what should I run other than "show lockedvnodes" and "show threads"? > Also, can anyone else try these steps and verify if they cause the > same problem for you? I repeat you recipe on CURRENT. What I got was the completely unresponsively system, that was _not_ deadlocked. It has slowly made a progress. Slowness is surely related to hole in the file backing fsck'ed (and snapshotted) filesystem. Snapshotting slowly made a progress, with lot of disk activity. After it had finished, system resumed normal operation. Tor Egge committed several fixes into CURRENT, that certainly help in this situation. >=20 > In my initial tests, filed in a PR, steps #1 and #2 were unnecessary > as I was working with real disks. The result is the same here. Still, > I am curious if anyone else can get the same result with a real disk > >=3D200GB in size. I am unable to duplicate it with a 20GB partition, > and I am not sure why. >=20 > -- > David 'dpk' Kirchner --ewQ5hdP4CtoTt3oD Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFEW0g+C3+MBN1Mb4gRAvDVAJ9QMHMrazK7lnYEIAAXFOIu4xR/1gCgo6QC xwrZo7eUAFqDbqLY3l+Rz4I= =aOET -----END PGP SIGNATURE----- --ewQ5hdP4CtoTt3oD--
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