From owner-freebsd-stable@FreeBSD.ORG Sat Nov 13 02:27:12 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 03C751065672; Sat, 13 Nov 2010 02:27:12 +0000 (UTC) (envelope-from mm@FreeBSD.org) Received: from mail.vx.sk (mail.vx.sk [IPv6:2a01:4f8:100:1043::3]) by mx1.freebsd.org (Postfix) with ESMTP id 459958FC16; Sat, 13 Nov 2010 02:27:11 +0000 (UTC) Received: from core.vx.sk (localhost [127.0.0.1]) by mail.vx.sk (Postfix) with ESMTP id 4405E11C005; Sat, 13 Nov 2010 03:27:08 +0100 (CET) X-Virus-Scanned: amavisd-new at mail.vx.sk Received: from mail.vx.sk ([127.0.0.1]) by core.vx.sk (mail.vx.sk [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Qe5JL+6kd74J; Sat, 13 Nov 2010 03:27:06 +0100 (CET) Received: from [10.9.8.1] (188-167-78-139.dynamic.chello.sk [188.167.78.139]) by mail.vx.sk (Postfix) with ESMTPSA id B0C8511BFFB; Sat, 13 Nov 2010 03:27:05 +0100 (CET) Message-ID: <4CDDF77B.90708@FreeBSD.org> Date: Sat, 13 Nov 2010 03:27:07 +0100 From: Martin Matuska User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; sk; rv:1.8.1.23) Gecko/20090812 Lightning/0.9 Thunderbird/2.0.0.23 Mnenhy/0.7.5.0 MIME-Version: 1.0 To: Andriy Gapon References: <4CDD2F5F.2000902@freebsd.org> <4CDD4EB4.40004@freebsd.org> In-Reply-To: <4CDD4EB4.40004@freebsd.org> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: freebsd-fs@freebsd.org, freebsd-stable@freebsd.org, Alexander Zagrebin Subject: Re: 8.1-STABLE: problem with unmounting ZFS snapshots X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Nov 2010 02:27:12 -0000 Yes, this is indeed a leak introduced by importing onnv revision 9214 and it exists in perforce as well - very easy to reproduce. # mount -t zfs test@t1 /mnt # umount /mnt (-> hang) http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6604992 http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6810367 This is not compatible with mounting snapshots outside mounted ZFS and I was not able to reproduce the errors defined in 6604992 and 6810367 (they are Solaris-specific). I suggest we comment out this code (from head, later MFC and p4 as well). Patch (should work with HEAD and 8-STABLE): http://people.freebsd.org/~mm/patches/zfs/zfs_vfsops.c.patch Dňa 12.11.2010 15:27, Andriy Gapon wrote / napísal(a): > on 12/11/2010 16:00 Alexander Zagrebin said the following: >> Thanks for your reply! >> >>>> 2. the umount is waiting for disk >>>> #ps | egrep 'PID|umount' >>>> PID TT STAT TIME COMMAND >>>> 958 0 D+ 0:00,04 umount /mnt >>>> # procstat -t 958 >>>> PID TID COMM TDNAME CPU PRI >>> STATE WCHAN >>>> 958 100731 umount - 3 133 >>> sleep mntref >>> >>> procstat -kk >> >> $ ps a | grep umount >> 86874 2- D 0:00,06 umount /mnt >> 90433 3 S+ 0:00,01 grep umount >> >> $ sudo procstat -kk 86874 >> PID TID COMM TDNAME KSTACK >> 86874 100731 umount - mi_switch+0x176 >> sleepq_wait+0x42 _sleep+0x317 vfs_mount_destroy+0x5a dounmount+0x4d4 >> unmount+0x38b syscall+0x1cf Xfast_syscall+0xe2 >> > > > Looks like possible mnt_ref leak. > I think that something like that was fixed some not long time ago. > Perhaps you either don't have the fix or there is another leak. > What revision do you have? > > Perhaps Martin has an insight here. >