On 23/05/14 19:51, Konrad Rzeszutek Wilk wrote:
> On Thu, May 22, 2014 at 04:40:07PM +0200, Roger Pau Monne wrote:
>> We are missing a check to see if the backend supports persistent
>> grants on resume, meaning we will always run with the value fetched
>> from the firsts host on which we run on.
>>
>> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
>> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
>> Cc: David Vrabel <david.vra...@citrix.com>
>> ---
>> drivers/block/xen-blkfront.c | 23 ++++++++++++++++-------
>> 1 files changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
>> index efe1b47..00ae36b 100644
>> --- a/drivers/block/xen-blkfront.c
>> +++ b/drivers/block/xen-blkfront.c
>> @@ -1430,6 +1430,20 @@ static void split_bio_end(struct bio *bio, int error)
>> bio_put(bio);
>> }
>>
>> +static void blkfront_setup_persistent(struct blkfront_info *info)
>> +{
>> + unsigned int persistent;
>> + int err;
>> +
>> + err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
>> + "feature-persistent", "%u", &persistent,
>> + NULL);
>> + if (err)
>> + info->feature_persistent = 0;
>> + else
>> + info->feature_persistent = persistent;
>> +}
>> +
>> static int blkif_recover(struct blkfront_info *info)
>> {
>> int i;
>> @@ -1456,6 +1470,7 @@ static int blkif_recover(struct blkfront_info *info)
>> info->shadow_free = info->ring.req_prod_pvt;
>> info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
>>
>> + blkfront_setup_persistent(info);
>> rc = blkfront_setup_indirect(info);
>> if (rc) {
>> kfree(copy);
>> @@ -1851,13 +1866,7 @@ static void blkfront_connect(struct blkfront_info
>> *info)
>> if (!err && discard)
>> blkfront_setup_discard(info);
>>
>> - err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
>> - "feature-persistent", "%u", &persistent,
>> - NULL);
>> - if (err)
>> - info->feature_persistent = 0;
>> - else
>> - info->feature_persistent = persistent;
>> + blkfront_setup_persistent(info);
>
> Should we also flush the ones that are on the info->grants list if
> we turning it off?
This path is only taken on the first connection, further calls to
blkfront_connect from resume code don't get here, because they take the
BLKIF_STATE_SUSPENDED path and just call blkif_recover and return. And
on disconnection blkfront_connect doesn't even get called.
Roger.
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