Re: pread() over NFS (again) [1.5.5.4]

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 26, 2008, 22:04 UTC
Message-ID: <7vod5nq2dy.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20080626210556.GZ11793@spearce.org>

"Shawn O. Pearce" <spearce@spearce.org> writes:

Show 7 quoted lines

> We have a file position we saw once before as the start of a delta.
> We wrote it down to disk.  We want to go back and open it up, as
> we have the base decompressed and in memory and need to compute
> the SHA-1 of the object that resides at this offset.
>
> And *wham* we get an EOF.  Where there should be data.  Where we
> know there is data.

We have written that earlier in the same process? Are we playing games with mixed mmap() and pread()? Is fsync() or msync() or unmap/remap needed?

> Actually, I think the last time someone reported something like this
> in Git it turned out to be an NFS kernel bug.  I didn't quote it
> in my reply to him, but I think he did say this was a linux client,
> linux server.

This is getting into the area Linus would immediately know the answer to, but he is away for this week.