fsck strangeness

[Karol Kwiatkowski]

Ian Smith wrote:
> On Thu, 23 Aug 2007, Karol Kwiatkowski wrote:
>  > Ian Smith wrote:
>  > > On Wed, 22 Aug 2007, Chris wrote:
>  > >  > If its bad to run fsck on a mounted read,write then why does
>  > >  > background fsck do it? or you talking about foreground fsck only?
>  > > 
>  > > Well I was referring to foreground fsck, and I still don't know why
>  > > running it on a mounted fs is 'bad' when fsck runs in 'NO WRITE' mode
>  > > anyway when it finds a fs is mounted, hence my query above.
>  > 
>  > Here's my understanding:
>  > 
>  > Mounted fs (rw) isn't in stable state, there may be some writes to it -
>  > daemons, buffers flushes, etc. In this condition fsck can report
>  > inconsistency. And fsck running in 'NO WRITE' won't help anyway :)
> 
> a) Absolutely.
> 
> b) Indeed it usually does, fairly consistently, especially on /var.
> 
> c) No it won't help (except where it can help locate problems in a real 
> mess like bad blocks), but the assertion in question was, can it hurt?

Ah sorry, I missed that. With 'NO WRITE' one can suppose it shouldn't
hurt anything except performance ;)

I made a quick scan through the source and it looks like it won't:

- in src/sbin/fsck_ffs/setup.c
if fs is mounted rw fswritefd is set to -1

- in src/sbin/fsck_ffs/fsutil.c
blwrite(), flush() and ckfini() won't write anything if fswritefd<0

Unless, of course, I'm missing something.

Cheers,

Karol

-- 
Karol Kwiatkowski   <karol.kwiat at gmail dot com>
OpenPGP 0x06E09309

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