2017-07-26 14:32:39

by Stefan Hajnoczi

[permalink] [raw]
Subject: [PATCH] virtio_blk: fix incorrect message when disk is resized

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 <[email protected]>
---
drivers/block/virtio_blk.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

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


2017-08-04 09:38:04

by Stefan Hajnoczi

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

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 <[email protected]>
> ---
> 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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2017-08-04 13:24:48

by Michael S. Tsirkin

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

On Fri, Aug 04, 2017 at 10:37:54AM +0100, Stefan Hajnoczi wrote:
> 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 <[email protected]>
> > ---
> > drivers/block/virtio_blk.c | 16 ++++++++++------
> > 1 file changed, 10 insertions(+), 6 deletions(-)
>
> Ping?

Oops - I thought I sent it up. Will do.

> > 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
> >