Hello;

Regretfully, your pseudocode is a bit too vague, would it be possible for you to be a bit more specific, particularly on your open() call?

That might make it easier for folks to figure out what is going wrong.

tnx!

johnu
________________________________________
From: linux-fsdevel-owner@vger.kernel.org [linux-fsdevel-owner@vger.kernel.org] on behalf of Ma, Jianpeng [jianpeng.ma@intel.com]
Sent: Tuesday, August 19, 2014 9:05 PM
To: viro@zeniv.linux.org.uk
Cc: Sage Weil; Mark Kirkwood; linux-aio@kvack.org; linux-fsdevel@vger.kernel.org
Subject: [HELP]:  about aio+dio

Hi all,
   At present, I met a problem.
Open(block, DIRECT_IO)
Io_submit()--->write operation
Close()
Exit(0)

After exit(), we found the content of block changed. If we only use aio, the bug can't reproduce.

Q1: Is close() wait until all aio to complete? Is exit() to wait until aio to complete?
Q2:Who may change the content? The program don't change.
Q3:My guess: only using aio, after io_submit, the content already copy to kernel from use-space. But for direct, kernel can't copy.
Later kernel do direct_io but the content changed.


Thanks!
Jianpeng Ma
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