linux-ext4 - Re: Files full of zeros with coreutils-8.11 and xfs (FIEMAP related?)

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Message-ID: <4DA74771.5010103@draigBrady.com>
Date:	Thu, 14 Apr 2011 20:13:53 +0100
From:	Pádraig Brady <P@...igBrady.com>
To:	Jim Meyering <jim@...ering.net>
CC:	Eric Sandeen <sandeen@...deen.net>, linux-ext4@...r.kernel.org,
	coreutils@....org, Markus Trippelsdorf <markus@...ppelsdorf.de>,
	xfs-oss <xfs@....sgi.com>
Subject: Re: Files full of zeros with coreutils-8.11 and xfs (FIEMAP related?)

On 14/04/11 18:27, Jim Meyering wrote:
> 
> FYI, I see the same failure now using ext3 (and but not w/ext4)
> with rawhide's 2.6.39-0.rc2.git0.0.fc16.x86_64:
> 
>   + df -t ext3 .

Not with ext3 ...

>   + mkfs -t ext4 -F blob

... but with ext4 loop back

>   + perl -e 'BEGIN { $n = 1 * 1024; *F = *STDOUT }' -e 'for (1..1) { sysseek (*F, $n, 1)' -e '&& syswrite (*F, chr($_)x$n) or die "$!"}'

>   + cp --sparse=always j1 j2
>   + cmp j1 j2
>   j1 j2 differ: char 1, line 1     <<<<================

But there was no preallocation done above.
So this was the original sync issue, which doesn't seem to be working :(
Is there a chance the rawhide kernel hasn't included that change?
Unlikely as it's 2.6.39-rc2.

cheers,
Pádraig.

p.s. I will do some checking with ext3 to ensure everything is OK
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