Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!vsi1!wyse!mips!rogerk
From: rogerk@mips.COM (Roger B.A. Klorese)
Newsgroups: comp.sys.mips
Subject: Re: root file system not checked on reboot
Message-ID: <24497@abbott.mips.COM>
Date: 1 Aug 89 21:59:45 GMT
References: <4529@watvlsi.waterloo.edu>
Reply-To: rogerk@mips.COM (Roger B.A. Klorese)
Distribution: comp
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 17

In article <4529@watvlsi.waterloo.edu> peregier@watvlsi.waterloo.edu (Phil Regier) writes:
>How a command like fsstat can determine when a root file system needs
>checking without actually running fsck is beyond me.

It does some of the preliminary work of fsck.  It checks for a superblock, and
tests the BFS_CLEAN and BFS_MOUNT bits.  As BFS_CLEAN is set by fsck, and
reset by mount if it discovers that it was mounted at the time the system 
went down, this is being used to predict the cleanness of the filesystem.

The logic seems to be that the only way to have a damaged filesystem if it
was dismounted cleanly would be if something scribbled on the unmounted
device file.
-- 
ROGER B.A. KLORESE      MIPS Computer Systems, Inc.      phone: +1 408 720-2939
928 E. Arques Ave.  Sunnyvale, CA  94086                        rogerk@mips.COM
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"I want to live where it's always Saturday."  -- Guadalcanal Diary