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Message-ID: <4DA71D83.5040601@sandeen.net> Date: Thu, 14 Apr 2011 11:14:59 -0500 From: Eric Sandeen <sandeen@...deen.net> To: Markus Trippelsdorf <markus@...ppelsdorf.de> CC: Pádraig Brady <P@...igBrady.com>, xfs-oss <xfs@....sgi.com>, linux-ext4@...r.kernel.org, coreutils@....org Subject: Re: Files full of zeros with coreutils-8.11 and xfs (FIEMAP related?) On 4/14/11 11:03 AM, Markus Trippelsdorf wrote: > On 2011.04.14 at 10:56 -0500, Eric Sandeen wrote: ... >> well, if I simply take the preallocation step out of the testcase, it works fine on xfs without a sync. >> >> So I still don't know what Markus hit... > > Maybe it's delalloc: > > x4 /tmp # dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=k > 10+0 records in > 10+0 records out > 5120 bytes (5.1 kB) copied, 0.0021822 s, 2.3 MB/s > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 0 16 unknown,delalloc,eof > k: 1 extent found > x4 /tmp # sync > x4 /tmp # filefrag -v k > Filesystem type is: 58465342 > File size of k is 5120 (2 blocks, blocksize 4096) > ext logical physical expected length flags > 0 0 26960045 16 eof > k: 1 extent found > well filefrag still returns that it knows of a valid range from logical blocks 0 to 16, so cp should have something to copy... -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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