Re: objrmap and vmtruncate

Benjamin LaHaise
2003-04-22T18:04:19Z

On Tue, Apr 22, 2003 at 01:34:46PM -0400, Ingo Molnar wrote:
> is anything forcing us to fixing up mappings during a truncate? What we
> need is just for the FS to recognize pages behind end-of-inode to still
> potentially exist after truncation, if those areas were mapped before the
> truncation. Apps that do not keep uptodate with truncaters can get
> out-of-date data anyway, via read()/write() anyway. Are there good
> arguments to be this strict across truncate()? We sure could make it safe
> even thought it's not safe currently.

Yes: access beyond EOF is required to SIGBUS according to various
standards. But keep in mind that this is a slow path and doesn't have to
be anywhere near optimal, unlike page reclaim.

-ben
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