Re: [9fans] file server trouble

[forsyth@vitanuova.com]

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i wouldn't necessarily suspect the drive.

it's saying that the fworm bitmap claims a
block has already been written, which isn't allowed
on a write-once structure.  thats fine, except
it might have been interrupted at some point when
the fworm bitmap had been written but pointers
in the super block and other structures updating
the allocation addresses had not been written.  the data might
or might not be in those blocks.
actually, i'd suspect it had crashed or rebooted
during a dump.

do the recover again, but try a kernel that uses a larger value in cw.c for
	h->fsize = s->fsize + 100;		/* this must be conservative */

you could also just comment out the fworm diagnostic.
i've done that in the past but i knew it was safe in those
cases because i had a clearer picture of its state when it crashed.


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To: 9fans@cse.psu.edu
Subject: Re: [9fans] file server trouble
Date: Wed, 3 Apr 2002 11:39:44 -0500
Message-ID: <20020403164150.3E2F319A55@mail.cse.psu.edu>

thanks to geoff's pointers, i was able to build a kernel that
correctly recovered my file system. the file server is back
up, and stays running in the face of normal use. but things
still arn't "right". i'm now getting lots of messages of the
following form on my file server console:

fworm: write 152116
cwio: write induced dump error - w worm
fworm: write 152117
cwio: write induced dump error - w worm
fworm: write 152151
cwio: write induced dump error - w worm
fworm: write 152152
cwio: write induced dump error - w worm

this started after a dump was attempted. the above block
would repeat every few seconds (~10). after the next
dump, a new set was generated, with about twice the
number of errors, printing about ever 20 seconds. this
looks to me like a bad disk (which is really annoying, since
it's a few months old). do others agree?

between now and when i can get the disk replaced, is
there any mechanism in the fs kernel for marking blocks
"bad"? and if not, am i correct in my belief that all my
dumps into the future will be unsafe, since dumps include
all the previous blocks (until modification)?