[PATCH nvme-cli] fabrics: Use corresponding hostid when hostnqn is generated

[Daniel Wagner]

Hi Shin'ichiro,

sorry for my late response.

On Sun, Jul 02, 2023 at 11:23:46AM +0900, Shin'ichiro Kawasaki wrote:
> After the kernel commit ae8bd606e09b ("nvme-fabrics: prevent overriding
> of existing host"), kernel ensures hostid and hostnqn maintain 1:1
> mapping and "non 1:1 mapping will be rejected". This makes 'nvme
> discover' and 'nvme connect' commands fail when they generate hostnqn,
> since it does not use corresponding hostid.
> 
> To avoid the failures, prepare and use corresponding hostid to the
> generated hostnqn, taking the hostid from the hostnqn string. Also warn
> when the hostid is different from that in hostid file.
> 
> Link: https://lore.kernel.org/linux-nvme/l7vk7fnzltpmvkwujsbf2btrzip6wh7ug62iwa3totqcda25l6@siqx7tj6lt3l/
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>
> ---
>  fabrics.c | 28 ++++++++++++++++++++++++++--
>  1 file changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/fabrics.c b/fabrics.c
> index ac240cad..2eeea48c 100644
> --- a/fabrics.c
> +++ b/fabrics.c
> @@ -677,6 +677,26 @@ static int nvme_read_volatile_config(nvme_root_t r)
>  	return ret;
>  }
>  
> +char *nvmf_hostid_from_hostnqn(const char *hostnqn)
> +{
> +	const char *uuid;
> +	const char *hostid_from_file;
> +
> +	if (!hostnqn)
> +		return NULL;
> +
> +	uuid = strstr(hostnqn, "uuid:");
> +	if (!uuid)
> +		return NULL;
> +	uuid += strlen("uuid:");
> +
> +	hostid_from_file = nvmf_hostid_from_file();
> +	if (hostid_from_file && strcmp(uuid, hostid_from_file))
> +		fprintf(stderr, "warning: use generated hostid instead of hostid file\n");
> +

As mentioned in my my other original mail, I'd say it makes sense to have the
check after ...

> +	return strdup(uuid);
> +}
> +
>  int nvmf_discover(const char *desc, int argc, char **argv, bool connect)
>  {
>  	char *subsysnqn = NVME_DISC_SUBSYS_NAME;
> @@ -753,8 +773,10 @@ int nvmf_discover(const char *desc, int argc, char **argv, bool connect)
>  	hostid_arg = hostid;
>  	if (!hostnqn)
>  		hostnqn = hnqn = nvmf_hostnqn_from_file();
> -	if (!hostnqn)
> +	if (!hostnqn) {
>  		hostnqn = hnqn = nvmf_hostnqn_generate();
> +		hostid = hid = nvmf_hostid_from_hostnqn(hostnqn);
> +	}
>  	if (!hostid)
>  		hostid = hid = nvmf_hostid_from_file();
>  	h = nvme_lookup_host(r, hostnqn, hostid);
> @@ -966,8 +988,10 @@ int nvmf_connect(const char *desc, int argc, char **argv)
>  
>  	if (!hostnqn)
>  		hostnqn = hnqn = nvmf_hostnqn_from_file();
> -	if (!hostnqn)
> +	if (!hostnqn) {
>  		hostnqn = hnqn = nvmf_hostnqn_generate();
> +		hostid = hid = nvmf_hostid_from_hostnqn(hostnqn);
> +	}
>  	if (!hostid)
>  		hostid = hid = nvmf_hostid_from_file();

... here

>  	h = nvme_lookup_host(r, hostnqn, hostid);
> -- 
> 2.40.1
> 

The rest looks good.

Thanks,
Daniel