linux-kernel - Re: fiemap is broken for sparse file in ext4?

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Message-ID: <AANLkTim9xIyL842wapccPIwEPVgd3BY8_r0tBGfGgvOt@mail.gmail.com>
Date:	Fri, 11 Jun 2010 12:46:44 -0400
From:	Greg Freemyer <greg.freemyer@...il.com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	Tao Ma <tao.ma@...cle.com>, linux-ext4@...r.kernel.org,
	Theodore Tso <tytso@....edu>, linux-kernel@...r.kernel.org
Subject: Re: fiemap is broken for sparse file in ext4?

On Fri, Jun 11, 2010 at 11:46 AM, Eric Sandeen <sandeen@...hat.com> wrote:
> Tao Ma wrote:
>
>>> What are you using to call fiemap?  Here it seems to be working:
>> I just wrote a simple test program by calling ioctl. It is attached.
>> btw, you need to call it immediately after dd so that we have a chance
>> that ext4 don't have time to allocate extents. ;)
>
> OK I take it back, I do see it.  *cough* too many different filesystems
> on this box ... ;)
>
> Yes, it does look like a bug.
>
> -Eric

I'm not clear how this is supposed to work.

Is this just a userspace bug in that FIEMAP_FLAG_SYNC is needed in the
fiemap call, or is there a kernel bug as well?

If fiemap is called with the FIEMAP_FLAG_SYNC flag is there currently a problem?

Thanks
Greg
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