From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <7ea713cb549c1d7b91a32c77987b62c2@collyer.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] truncation via wstat on ken's fs
Date: Sun, 17 Oct 2004 17:43:25 -0700
From: geoff@collyer.net
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Good point, Russ, and I had done something similar (cloned dtrunc()
and added a length argument).

Ken frees blocks in reverse order (last block freed first), presumably
to assist repairs if the system should crash in the middle of it, or
something of the sort.  The obvious way to truncate is to walk to the
point of truncation, zero any partial block after it, then free data
blocks (and if feasible indirect blocks) while walking to EOF.  Doing
this backward is a little messier.