[Devel] [PATCH] fs/fuse kio: skip iostat count for unknown req types

[Pavel Butsykin]

On 03.06.2019 10:14, Kirill Tkhai wrote:
> On 03.06.2019 09:41, Pavel Butsykin wrote:
>>
>>
>> On 31.05.2019 19:06, Kirill Tkhai wrote:
>>> On 31.05.2019 12:23, Pavel Butsykin wrote:
>>>> There are still some number of response req types:
>>>> PCS_CS_WRITE_ZERO_RESP
>>>> PCS_CS_WRITE_HOLE_RESP
>>>> PCS_CS_REPLICATEX_RESP
>>>> PCS_CS_FIEMAP_RESP
>>>> PCS_CS_MAP_PROP_RESP
>>>>
>>>> It makes no sense to count statistics for such requests, so for them the stat
>>>> count will simply be skipped.
>>>>
>>>> Signed-off-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
>>>> ---
>>>>    fs/fuse/kio/pcs/fuse_stat.c | 7 ++++---
>>>>    1 file changed, 4 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/fs/fuse/kio/pcs/fuse_stat.c b/fs/fuse/kio/pcs/fuse_stat.c
>>>> index 06be3c75240c..31ff73d6c3dc 100644
>>>> --- a/fs/fuse/kio/pcs/fuse_stat.c
>>>> +++ b/fs/fuse/kio/pcs/fuse_stat.c
>>>> @@ -654,7 +654,6 @@ struct fuse_val_stat *req_stat_entry(struct pcs_fuse_io_stat *io, u32 type)
>>>>    		default:
>>>>    			break;
>>>>    	}
>>>> -	WARN_ON_ONCE(1);
>>>>    	return NULL;
>>>>    }
>>>>    
>>>> @@ -663,9 +662,11 @@ static void fuse_iostat_count(struct pcs_fuse_io_stat_sync *iostat,
>>>>    {
>>>>    	struct fuse_val_stat *se;
>>>>    
>>>> -	write_seqlock(&iostat->seqlock);
>>>>    	se = req_stat_entry(iostat->CURR(iostat), type);
>>>
>>> Shouldn't iostat->CURR(iostat) be obtained under seqlock?
>>>
>>
>> Yep, iostat->CURR(iostat) should be under seqlock, thanks for fixup!
> 
> I think it may be useful to add some lockdep check into CURR and other macros.

Yes, it makes sense, taking into account that it's not the most obvious
synchronization.

> Kirill
>