On Tue, Mar 08, 2005 at 01:18:14AM -0800, Andrew Morton wrote:
> Suparna Bhattacharya <[EMAIL PROTECTED]> wrote:
> >
> > ...
> >
> > Bugs in this area seem never-ending don't they - plug one, open up
> > another - hard to be confident/verify :( - someday we'll have to
> > rewrite a part of this code.
>
> It's solving a complex problem. Any rewrite would probably end up just as
> hairy once all the new bugs and corner cases are fixed. Maybe.
>
>
> > Hmm, shouldn't dio->result ideally have been adjusted to be within
> > i_size at the time of io submission, so we don't have to deal with
> > this during completion ? We are creating bios with the right size
> > after all.
> >
> > We have this:
> > if (!buffer_mapped(map_bh)) {
> > ....
> > if (dio->block_in_file >=
> > i_size_read(dio->inode)>>blkbits) {
> > /* We hit eof */
> > page_cache_release(page);
> > goto out;
> > }
> >
> > and
> > dio->result += iov[seg].iov_len -
> > ((dio->final_block_in_request - dio->block_in_file)
> > <<
> > blkbits);
> >
> >
> > can you spot what is going wrong here that we have to try and
> > workaround this later ?
>
> Good question. Do we have the i_sem coverage to prevent a concurrent
> truncate?
>
> But from Sebastien's description it doesn't soound as if a concurrent
> truncate is involved.
Daniel McNeil has a testcase that reproduces the problem - seemed
like a single thread thing - that's what puzzles me.
Regards
Suparna
--
Suparna Bhattacharya ([EMAIL PROTECTED])
Linux Technology Center
IBM Software Lab, India
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