Handling quota and out of space issues while holding an OpLock

Richard Sharpe rsharpe at richardsharpe.com
Mon Sep 20 17:04:06 GMT 2004


On Mon, 20 Sep 2004, David Collier-Brown wrote:

> Am Sonntag, 19. September 2004 19:11 schrieb Richard Sharpe:
> >>I have noticed that windows clients tend to send requests to extend the
> >>file size even though they are holding an oplock on a file.
> >>
> >>It struck me that this must be so they can deal with issues like out of
> >>quota or out of space at the point at which they occur  [...]
>
> Peter Waechtler wrote:
>  > [Discussion of checking writes]
> > And with regards to quota: when does a unix system checks the quota limit?
> > On Inode and block allocation time? Am I able to create a sparse file that is
> > beyond the limit - only getting an error on block allocation? I think so.
>
>    Yes, that's correct: standard Unix discovers it's out of space/quota
> only when it actually allocates the blocks of a "holey" file.
>
>    This came up in discussions here before, but I don't recollect what
> the resolution was. I do remember that space-filling was an expensive
> operation (;-)).  The quota code is mostly by Stefan (metze)
> Metzmacher...

For me, holey files are not an issue, I think.

Just writing a small VC++ app to test what actually happens ...

Regards
-----
Richard Sharpe, rsharpe[at]richardsharpe.com, rsharpe[at]samba.org,
sharpe[at]ethereal.com, http://www.richardsharpe.com


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