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SubjectRe: [PATCH V2 2/3] xen: scsiback: add LUN of restored domain
On 02/18/2015 06:02 PM, Boris Ostrovsky wrote:
> On 02/17/2015 02:02 AM, Juergen Gross wrote:
>> When a xen domain is being restored the LUN state of a pvscsi device
>> is "Connected" and not "Initialising" as in case of attaching a new
>> pvscsi LUN.
>>
>> This must be taken into account when adding a new pvscsi device for
>> a domain as otherwise the pvscsi LUN won't be connected to the
>> SCSI target associated with it.
>
>
> scsiback_do_add_lun() is being called from scsiback_frontend_changed()
> which eventually sets the state to Connected. Is the added test of
> 'try' an optimization or is it needed for correctness?

It's needed for correctness. In case of resume the translation entry
will be already existing, thus scsiback_add_translation_entry() will
return a value unequal to zero. We don't want to set the device state
to "Closed" in this case.

Juergen

>
> -boris
>
>
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>> drivers/xen/xen-scsiback.c | 19 ++++++++++++++-----
>> 1 file changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
>> index 9faca6a..9d60176 100644
>> --- a/drivers/xen/xen-scsiback.c
>> +++ b/drivers/xen/xen-scsiback.c
>> @@ -992,7 +992,7 @@ found:
>> }
>>
>> static void scsiback_do_add_lun(struct vscsibk_info *info, const
>> char *state,
>> - char *phy, struct ids_tuple *vir)
>> + char *phy, struct ids_tuple *vir, int try)
>> {
>> if (!scsiback_add_translation_entry(info, phy, vir)) {
>> if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
>> @@ -1000,7 +1000,7 @@ static void scsiback_do_add_lun(struct
>> vscsibk_info *info, const char *state,
>> pr_err("xen-pvscsi: xenbus_printf error %s\n", state);
>> scsiback_del_translation_entry(info, vir);
>> }
>> - } else {
>> + } else if (!try) {
>> xenbus_printf(XBT_NIL, info->dev->nodename, state,
>> "%d", XenbusStateClosed);
>> }
>> @@ -1060,10 +1060,19 @@ static void scsiback_do_1lun_hotplug(struct
>> vscsibk_info *info, int op,
>>
>> switch (op) {
>> case VSCSIBACK_OP_ADD_OR_DEL_LUN:
>> - if (device_state == XenbusStateInitialising)
>> - scsiback_do_add_lun(info, state, phy, &vir);
>> - if (device_state == XenbusStateClosing)
>> + switch (device_state) {
>> + case XenbusStateInitialising:
>> + scsiback_do_add_lun(info, state, phy, &vir, 0);
>> + break;
>> + case XenbusStateConnected:
>> + scsiback_do_add_lun(info, state, phy, &vir, 1);
>> + break;
>> + case XenbusStateClosing:
>> scsiback_do_del_lun(info, state, &vir);
>> + break;
>> + default:
>> + break;
>> + }
>> break;
>>
>> case VSCSIBACK_OP_UPDATEDEV_STATE:
>>
>
> --
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