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From: Andreas Dilger <adilger@clusterfs.com>
To: Valerie Clement <valerie.clement@bull.net>
Cc: Theodore Tso <tytso@mit.edu>,
	ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: [RFC][PATCH 2/11][take 2] add new macro EXT2_DESC_PER_BLOCK in e2fsprogs
Date: Thu, 21 Jun 2007 13:16:14 -0600	[thread overview]
Message-ID: <20070621191614.GX5181@schatzie.adilger.int> (raw)
In-Reply-To: <467A95F5.6050300@bull.net>

On Jun 21, 2007  17:15 +0200, Valerie Clement wrote:
> -#define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
> +#define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / \
> +	((EXT2_DESC_SIZE(s) >= EXT2_MIN_DESC_SIZE_64BIT) ? \
> +	 (s)->s_desc_size : sizeof(struct ext2_group_desc)))

If EXT2_DESC_SIZE() is already checking the superblock flag, why not just use:

#define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s))

Even better would be (1 << (EXT2_BLOCK_SIZE_BITS(s) - EXT2_DESC_SIZE_BITS(s))).

Having the s_desc_size stored as an integer shift (128 << s_desc_bits) instead
of a number of bytes makes a lot of sense (forces power-of-two size, makes
math easy), but it might be too much of a format change at this point?


Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.

      reply	other threads:[~2007-06-21 19:16 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-21 15:15 [RFC][PATCH 2/11][take 2] add new macro EXT2_DESC_PER_BLOCK in e2fsprogs Valerie Clement
2007-06-21 19:16 ` Andreas Dilger [this message]

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