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From: Frode Nordahl <frode@nordahl.net>
Date: Fri, 4 Jun 2004 17:06:03 +0200
To: Kirk McKusick <mckusick@beastie.mckusick.com>
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cc: freebsd-current@freebsd.org
Subject: UFS snapshot deadlocks
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Hello,

There has been some talk about reproducible UFS snapshot deadlocks for 
some time now on the lists, and I have not seen any recent talk about 
it.

Anyone know if there has been any progress on this issue?

The following is a 100% reproducible procedure to make it happen:

Running 5.2-CURRENT #0: Fri Jun  4 15:07:54 CEST 2004

tty1:
while (1)
	ls -la /usr/.snap
end

tty2:
dump -0af /some/where -C 32 -L /dev/ad0s1f

Looking at top(1) show mksnap_ffs being in state UFS.

I also experienced this on one of my NFS servers, when I accidently 
toyed around with ls while I started the dump. It was then hung in 
state getblk.

Cheers,
Frode