linux-ext4 - files mapped funny? (related to online defragmentation)

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Message-Id: <1179755398.389.24.camel@eric-laptop>
Date:	Mon, 21 May 2007 06:49:58 -0700
From:	Eric <erpo41@...il.com>
To:	linux-ext4 <linux-ext4@...r.kernel.org>
Subject: files mapped funny? (related to online defragmentation)

Hi,

I'm getting strange results when I map out the blocks used in files
larger than a several thousand KB. I never seem to get any more than
1024 contiguous data blocks in a row. 

Here's a portion of the output of my script when I run it on a 176MB
file in my home directory:
...
Contiguous chunk 67: 2385568 - 2385591  (24 blocks)
Contiguous chunk 68: 2385608 - 2386448  (841 blocks)
Contiguous chunk 69: 2386450 - 2387473  (1024 blocks)
Contiguous chunk 70: 2387475 - 2388498  (1024 blocks)
Contiguous chunk 71: 2388500 - 2389523  (1024 blocks)
...

Maybe this is a bug in my script? Can anyone explain why this would
happen?

I'm attaching my script in case other ext2/3/4 newbies can get any use
out of it, and in case anyone needs to see it in order to answer my
question. It's pretty self-explanatory, though.

Cheers,

Eric

View attachment "fibmap.py" of type "text/x-python" (1611 bytes)

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