2011-07-09 16:02:24

by Janson

[permalink] [raw]
Subject: A problem about pnfs+ext4

In the pnfs + ext4 test,we found a problem: when writting a file in pnfs
we can not read the contents from ext4. After studying we found that
ext4 extent have a initialize flag, when pnfs call fallocate, the flag will
be set to 1, but after pnfs writting data by truncate, the flags can not
be set to 0. If the flag is 1,ext4 can not read the content.
Now,in ext4 code,The only wan that ext4 set the flag to 0 is DIO.
Do you know how to solve this problem?


Best regards,
Janson


2011-07-14 17:59:11

by Benny Halevy

[permalink] [raw]
Subject: Re: A problem about pnfs+ext4

Hi Janson, I started looking at this.
This seems is a genuine issue with the current implementation.
It might take me a while to give you a patch to test
due to other burning stuff on my queue.
But anyhow, thanks for reporting this!

Benny

On 2011-07-09 18:47, Janson wrote:
> In the pnfs + ext4 test,we found a problem: when writting a file in pnfs
> we can not read the contents from ext4. After studying we found that
> ext4 extent have a initialize flag, when pnfs call fallocate, the flag will
> be set to 1, but after pnfs writting data by truncate, the flags can not
> be set to 0. If the flag is 1,ext4 can not read the content.
> Now,in ext4 code,The only wan that ext4 set the flag to 0 is DIO.
> Do you know how to solve this problem?
>
>
> Best regards,
> Janson
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