Re: ext2 large block size > page size

From: Mason
Date: Fri Apr 01 2011 - 10:16:56 EST


Hello again,

Mason wrote:

As far as I can tell from a quick Google search,
there was a push in 2007 to add support for large
blocks in some file-systems, in particular ext2.

e.g. cf. http://lwn.net/Articles/239090/

The page above describes one of the proposed patch, and
the following article by Jonathan Corbet gives an overview
of the issues.

http://lwn.net/Articles/232757/

Was this ever accepted into the main line?
(It seems to have lived within -mm for a while)

A few years later, I'm trying to mount a HDD
which was ext2-formatted with 32k blocks.

And mount is failing (with a strange "block size
too small" error message).

I'm trying this in Fedora 14
2.6.35.6 kernel
1.41.12 e2fsprogs

To add insult to injury, Ext2Fsd(*) an ext2 IFS (Installable
File System) for Windows, accepts large-block ext2 partitions.

(*) http://www.ext2fsd.com/

Is the support for large blocks in ext2 not compiled in
this generic kernel ? Or was the patch never accepted ?

I'm working with a ST Microelectronics set-top box.
Here are a few performance results for a 2TB USB HDD:
block size 4k : format = 151 s / mount = 242 s
block size 8k : format = 52 s / mount = 71 s
block size 16k : format = 30 s / mount = 36 s
block size 32k : format = 18 s / mount = 19 s

Using 4kB blocks makes mount too slow on the STB, which
is why I'd like to use larger blocks. It would be nice
if the movies recorded on the STB could also be read on
a Linux PC.

Is there, perhaps, a better place to discuss this issue?

--
Regards, Mason

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