linux-kernel - Re: [RFC] block: check partition alignment

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Date:   Wed, 14 Dec 2016 09:07:19 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     Stefan Haberland <sth@...ux.vnet.ibm.com>
Cc:     axboe@...nel.dk, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, hoeppner@...ux.vnet.ibm.com,
        sebott@...ux.vnet.ibm.com
Subject: Re: [RFC] block: check partition alignment

> To prevent partitions that are not aligned to the physical blocksize
> of a device check for the alignment in the blkpg_ioctl.

We'd also need to reject this when reading partitions from disk, right?

> +			/* check if partition is aligned to blocksize */
> +			if (p.start % bdev_physical_block_size(bdev) != 0)

And this should be bdev_logical_block_size, as the logical block size
is the only thing that matters for the OS - exposing the physical block
size is just an optional hint to prevent users from doing stupid
things (like creating unaligned partitions :))