Re: [PATCH] virtio_blk: fix incorrect message when disk is resized

From: Stefan Hajnoczi
Date: Fri Aug 04 2017 - 05:38:07 EST


On Wed, Jul 26, 2017 at 03:32:23PM +0100, Stefan Hajnoczi wrote:
> The message printed on disk resize is incorrect. The following is
> printed when resizing to 2 GiB:
>
> $ truncate -s 1G test.img
> $ qemu -device virtio-blk-pci,logical_block_size=4096,...
> (qemu) block_resize drive1 2G
>
> virtio_blk virtio0: new size: 4194304 4096-byte logical blocks (17.2 GB/16.0 GiB)
>
> The virtio_blk capacity config field is in 512-byte sector units
> regardless of logical_block_size as per the VIRTIO specification.
> Therefore the message should read:
>
> virtio_blk virtio0: new size: 524288 4096-byte logical blocks (2.15 GB/2.0 GiB)
>
> Note that this only affects the printed message. Thankfully the actual
> block device has the correct size because the block layer expects
> capacity in sectors.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
> ---
> drivers/block/virtio_blk.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)

Ping?

> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 4e02aa5fdac0..69a2d1748743 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -381,6 +381,7 @@ static void virtblk_config_changed_work(struct work_struct *work)
> struct request_queue *q = vblk->disk->queue;
> char cap_str_2[10], cap_str_10[10];
> char *envp[] = { "RESIZE=1", NULL };
> + unsigned long long nblocks;
> u64 capacity;
>
> /* Host must always specify the capacity. */
> @@ -393,16 +394,19 @@ static void virtblk_config_changed_work(struct work_struct *work)
> capacity = (sector_t)-1;
> }
>
> - string_get_size(capacity, queue_logical_block_size(q),
> + nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
> +
> + string_get_size(nblocks, queue_logical_block_size(q),
> STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
> - string_get_size(capacity, queue_logical_block_size(q),
> + string_get_size(nblocks, queue_logical_block_size(q),
> STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
>
> dev_notice(&vdev->dev,
> - "new size: %llu %d-byte logical blocks (%s/%s)\n",
> - (unsigned long long)capacity,
> - queue_logical_block_size(q),
> - cap_str_10, cap_str_2);
> + "new size: %llu %d-byte logical blocks (%s/%s)\n",
> + nblocks,
> + queue_logical_block_size(q),
> + cap_str_10,
> + cap_str_2);
>
> set_capacity(vblk->disk, capacity);
> revalidate_disk(vblk->disk);
> --
> 2.13.3
>

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