On Wed, Dec 19, 2012 at 08:40:15PM +0100, Alexander Graf wrote:
> When a file system is mounted on a virtio-blk disk, we then remove it
> and then reattach it, the reattached disk gets the same disk name and
> ids as the hot removed one.
>
> This leads to very nasty effects - mostly rendering the newly attached
> device completely unusable.
>
> Trying what happens when I do the same thing with a USB device, I saw
> that the sd node simply doesn't get free'd when a device gets forcefully
> removed.
>
> Imitate the same behavior for vd devices. This way broken vd devices
> simply are never free'd and newly attached ones keep working just fine.
>
> Signed-off-by: Alexander Graf <agraf@xxxxxxx>
> ---
> drivers/block/virtio_blk.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 0bdde8f..07a18e2 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -889,6 +889,7 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
> {
> struct virtio_blk *vblk = vdev->priv;
> int index = vblk->index;
> + int refc;
>
> /* Prevent config work handler from accessing the device. */
> mutex_lock(&vblk->config_lock);
> @@ -903,11 +904,15 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
>
> flush_work(&vblk->config_work);
>
> + refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
> put_disk(vblk->disk);
> mempool_destroy(vblk->pool);
> vdev->config->del_vqs(vdev);
> kfree(vblk);
> - ida_simple_remove(&vd_index_ida, index);
> +
> + /* Only free device id if we don't have any users */
> + if (refc == 1)
> + ida_simple_remove(&vd_index_ida, index);
> }
>
> #ifdef CONFIG_PM
Network devices take the approach of retrying every second.
Donnu if it makes sense here.
> --
> 1.7.12.4
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