On 06/13/2019 12:01 PM, Josef Bacik wrote:
> On Wed, May 29, 2019 at 03:16:06PM -0500, Mike Christie wrote:
>> If the device is setup with ioctl we can resize the device after the
>> initial setup, but if the device is setup with netlink we cannot use the
>> resize related ioctls and there is no netlink reconfigure size ATTR
>> handling code.
>>
>> This patch adds netlink reconfigure resize support to match the ioctl
>> interface.
>>
>> Signed-off-by: Mike Christie <[email protected]>
>
> Sorry I missed this too, but I think there's a problem with this actually.
>
>> ---
>>
>> V3;
>> - If the device size or block size has not changed do not call
>> nbd_size_set.
>>
>> V2:
>> - Merge reconfig and connect resize related code to helper and avoid
>> multiple nbd_size_set calls.
>>
>> drivers/block/nbd.c | 48 ++++++++++++++++++++++++++++++---------------
>> 1 file changed, 32 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 236253fbf455..9486555e6391 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -1685,6 +1685,30 @@ nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
>> [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
>> };
>>
>> +static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
>> +{
>> + struct nbd_config *config = nbd->config;
>> + u64 bsize = config->blksize;
>> + u64 bytes = config->bytesize;
>> +
>> + if (info->attrs[NBD_ATTR_SIZE_BYTES])
>> + bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
>> +
>> + if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
>> + bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
>> + if (!bsize)
>> + bsize = NBD_DEF_BLKSIZE;
>> + if (!nbd_is_valid_blksize(bsize)) {
>> + printk(KERN_ERR "Invalid block size %llu\n", bsize);
>> + return -EINVAL;
>> + }
>> + }
>> +
>> + if (bytes != config->bytesize || bsize != config->blksize)
>> + nbd_size_set(nbd, bsize, div64_u64(bytes, bsize));
>
> This part won't actually update the bdev if there already is one because
> nbd->task_recv is NULL for netlink related devices. Probably need to fix that
I'm not sure I understand this part of the comment. For netlink we do:
nbd_genl_connect -> nbd_start_device:
nbd_start_device()
{
.....
nbd->task_recv = current;
> to update the bdev unconditionally, and then just see if bdget_disk() returns
> NULL in nbd_size_update. Also I hate myself for how many size update
> functions
> there are. Thanks,
>
> Josef
>
