kern/111766: "panic: ffs_blkfree: freeing free block" during disk activity

[Kris Kennaway]

The following reply was made to PR kern/111766; it has been noted by GNATS.

From: Kris Kennaway <kris at obsecurity.org>
To: Rong-En Fan <rafan at FreeBSD.org>
Cc: Kris Kennaway <kris at obsecurity.org>, FreeBSD-gnats-submit at FreeBSD.org
Subject: Re: kern/111766: "panic: ffs_blkfree: freeing free block" during disk activity
Date: Wed, 18 Apr 2007 00:22:07 -0400

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 On Wed, Apr 18, 2007 at 12:14:35PM +0800, Rong-En Fan wrote:
 > On Wed, Apr 18, 2007 at 12:06:15AM -0400, Kris Kennaway wrote:
 > > On Wed, Apr 18, 2007 at 12:01:53PM +0800, Rong-En Fan wrote:
 > > > I think I tried once but in vain. Some previous backtrace
 > > > at http://www.rafan.org/FreeBSD/panic/freeing_free_block/
 > > > I haven't see this since last Oct, but the filesystem does not
 > > > get full recently (we got larger disks).
 > >=20
 > > Unfortunately I dont think the backtrace is very useful, it's
 > > reporting damage that occured at some earlier time.
 > >=20
 > > > >From previous experience, usually the panic is triggered on
 > > > the full partition but I saw once or twice that it's triggered
 > > > on another non-full filesystem.
 >=20
 > Let me clear it a bit. When it's triggered on non-full filesystem,
 > I have another filesystem is full and some clients trying to write
 > to the full one.
 >=20
 > > I am not entirely sure whether it is really due to a full filesystem,
 > > because I've also come across it in random circumstances.  I have also
 > > spent some time stressing full filesystems without causing the panic.
 > > If you can come up with a way to reliably produce it, that would be
 > > very useful (possibly essential).
 >=20
 > Perhaps in the summer, I can find some free time to do this.
 > Just curious, have you tried exported the filesystem and stress
 > via nfs client?
 
 I didn't try that, but will give it a shot.
 
 Kris
 
 
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