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From: Eric Sandeen <sandeen@redhat.com>
To: Greg Freemyer <greg.freemyer@gmail.com>
Cc: Tao Ma <tao.ma@oracle.com>,
	linux-ext4@vger.kernel.org, Theodore Tso <tytso@mit.edu>,
	linux-kernel@vger.kernel.org
Subject: Re: fiemap is broken for sparse file in ext4?
Date: Fri, 11 Jun 2010 11:56:11 -0500	[thread overview]
Message-ID: <4C126AAB.4040802@redhat.com> (raw)
In-Reply-To: <AANLkTim9xIyL842wapccPIwEPVgd3BY8_r0tBGfGgvOt@mail.gmail.com>

Greg Freemyer wrote:
> On Fri, Jun 11, 2010 at 11:46 AM, Eric Sandeen <sandeen@redhat.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?

The flag is optional, though maybe filefrag should use it.

Without it, we should get the proper logical offset and a delalloc-flagged
extent returned

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

yep, we should get one delalloc extent in the results and we don't.

-Eric

> Thanks
> Greg

  reply	other threads:[~2010-06-11 16:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-11  2:15 fiemap is broken for sparse file in ext4? Tao Ma
2010-06-11  4:08 ` Eric Sandeen
2010-06-11  5:05   ` Tao Ma
2010-06-11 13:43     ` Eric Sandeen
2010-06-11 15:46     ` Eric Sandeen
2010-06-11 16:46       ` Greg Freemyer
2010-06-11 16:56         ` Eric Sandeen [this message]
2010-06-11 23:46           ` Tao Ma
2010-06-11 23:55             ` Eric Sandeen

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