Re: [RFC PATCH] nbd: set the default nbds_max to 0

From: Xiubo Li
Date: Wed May 29 2019 - 21:26:17 EST


On 2019/5/29 21:48, Josef Bacik wrote:
On Wed, May 29, 2019 at 04:08:36PM +0800, xiubli@xxxxxxxxxx wrote:
From: Xiubo Li <xiubli@xxxxxxxxxx>

There is one problem that when trying to check the nbd device
NBD_CMD_STATUS and at the same time insert the nbd.ko module,
we can randomly get some of the 16 /dev/nbd{0~15} are connected,
but they are not. This is because that the udev service in user
space will try to open /dev/nbd{0~15} devices to do some sanity
check when they are added in "__init nbd_init()" and then close
it asynchronousely.

Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---

Not sure whether this patch make sense here, coz this issue can be
avoided by setting the "nbds_max=0" when inserting the nbd.ko modules.

Yeah I'd rather not make this the default, as of right now most people still
probably use the old method of configuration and it may surprise them to
suddenly have to do nbds_max=16 to make their stuff work. Thanks,

Sure, make sense to me :-)

So this patch here in the mail list will as one note and reminder to other who may hit the same issue in future.

Thanks.
BRs
Xiubo


Josef