linux-ext4 - Re: [PATCH][e2fsprogs][mke2fs] fix FLEX

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Date:	Mon, 7 Jul 2008 12:46:07 -0400
From:	Theodore Tso <tytso@....EDU>
To:	Celine Bourde <celine.bourde@...l.net>
Cc:	linux-ext4@...r.kernel.org, "Jose R. Santos" <jrs@...ibm.com>,
	cmm@...ibm.com,
	Frédéric Bohé <frederic.bohe@...l.net>,
	SOLOFO RAMANGALAHY <Solofo.Ramangalahy@...l.net>,
	Jean-Pierre Dion <jean-pierre.dion@...l.net>
Subject: Re: [PATCH][e2fsprogs][mke2fs] fix FLEX_BG offset

On Thu, Jul 03, 2008 at 10:21:02AM +0200, Celine Bourde wrote:
> This patch resolves the offset problem of the flex_bg
> option when you use mke2fs tool.

Actually, I think the problem is a bigger one.  Ext2fs_get_free_blocks()
returns a error code on failure.  So the code before the conditional
you modified is totally bogus:

	/* Find the first available block */
	if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
				   &first_free))
		return first_free;

	if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
				   bmap, &first_free))
		return first_free;

	return first_free;

I think this should be instead:

	/* Find the first available block */
	if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
				   &first_free) == 0)
		return first_free;

	if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
				   bmap, &first_free) == 0)
		return first_free;

	/* 
	 * Oops, we weren't able to find enough space.  We return 
	 * first_free as a best try.
	 */

	return first_free;

							- Ted
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