Re: MSDOSFS woes

On Sat, Aug 02, 2003 at 06:08:50PM +0300, Ruslan Ermilov wrote:
> Gang, :-)
> 
> While working with Marcel on a bootable CD-ROM for IA64 issue,
> I've stumbled upon the following problem.  I needed to increase
> the size of the EFI partition (which is an MS-DOS file system)
> to 64M, and that made two of my machines stuck solidly -- a lot
> of process are waiting on the "wdrain" event.
> 
> The issue is not IA64 specific, both machines in question are
> i386.  The following script makes my machines unhappy:
> 
> EFISZ=131072
> dd if=/dev/zero of=$BASE/$EFIPART count=$EFISZ
> md=`mdconfig -a -t vnode -f $BASE/$EFIPART`
> newfs_msdos -F 12 -S 512 -h 4 -o 0 -s $EFISZ -u 16 $md
> mount -t msdosfs /dev/$md /mnt
> dd if=/dev/zero of=/mnt/foo
> 
> Changing to the -F 16 does not take any (good) effect.
> Anyone is interested in narrowing it down?
> 

I've also seen this happening on my Athlon XP system running -CURRENT.  I 
presumed it was the deadlock in vnode-backed md disks.  It seems that when
a lot of disk activity occurs on the md partition, the process stops - 
this is on a 30GB image containing UFS2 partitions /dev/md0s1[a,d,e].
Attempting to reboot results in the message 'processes would not die - ps
axl advised', I had to reset the computer because nothing more happened.

--
Bruce Cran