why msync() is not quoted by MMAP_NEED_MSYNC?

[Russ Allbery]

Katsuhiro Kondou <Katsuhiro_Kondou at isc.org> writes:

> While I installed latest cvs version on my iBook, I found innd dies when
> msync() is called at innd/icd.c.  msync() returns EINVAL, but from
> msync(2), I don't think innd misuses msync().  I'm suspecting potential
> bug in msync() on OSX, and have already reported to Apple.  OTTH, I
> think msync() is not required for innd on OSX, since the result of
> configure indicates;

> checking whether msync is needed... no

> I think we can quote '#ifdef MMAP_NEED_MSYNC' where msync() is used.
> Any thoughts?

You always want to msync periodically on all platforms or you lose all
your data in a crash.  MMAP_NEED_MSYNC only determines whether you need to
msync after every non-mmap write in order to see the results.

msync needs to be called with page-aligned addresses.  Some parts of INN
weren't doing that; I don't know if icd.c has that problem.  If so, the
msync_page function may help.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>

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