Subject: Re: locking problem on amd64 (w/ lfs)
To: Blair Sadewitz <>
From: Sarton O'Brien <>
List: current-users
Date: 12/04/2007 10:29:22
Blair Sadewitz wrote:
> I've found that LFS is more unstable if one uses non-default
> lseg/block/frag sizes when creating the filesystem.  At this time, I
> recommend sticking to 1MB/8k/1k.  Also:

I configured using defaults, disklabel reports:

4.4LFS   1024  8192     7

I just tried a dumpfs (which couldn't ID the filesystem) ... and before 
I assumed their was an lfs specific dumpfs, attempted it on the root 
filesystem ... which paniced. I'll post that in another email though ;)

> -- Don't disable vfs.lfs.ignore_lazy_sync; if you do, you'll likely
> end up with vnodes stuck in IN_PAGING.  This is not fun and makes it
> hard to sync disks upon shutdown.
> -- Use vfs.lfs.pagetrip with caution (this might apply to MP systems
> only).  The lower the value, the more likely it seems that you'll end
> up with a locking assertion or something else.  There is some funky
> problem when using this (seems to always involve the wakeup of the
> writer daemon, IIRC, though I can't seem to find the backtrace I wrote
> down last time this happened, so I'm not sure).  It may be related to
> the problem ad@ described.
>> I use it for /obj all the time, no tweaking, works great.
> Is this on a multiprocessor system?  Me too, so long as I don't
> deviate from the defaults it likes in any way. Also, I find that for
> some reason that completely escapes me, it is more unstable as a root
> filesystem.  Why?!? ;)

I've been using it as an smb/cifs share for about 6 months. Originally I 
saw panics nearly every second day but as kenerls have been updated, the 
last issue I saw was continual looping reported in dmesg.

Looking today, it seems to be running with no error.

I can reproduce a panic by handing the the disk to a xen3 domu, 
initiating samba on the domu, pointing to the mounted lfs, mounting the 
smb/cifs share under the dom0 and initiating a large file transfer.

I don't believe this is lfs specific though and I haven't got around to 
the copy and paste yet. From memory, there was lfs references in the 
debug though.