On 2/5/2017 18:37, Kinglong Mee wrote:
> On 2/4/2017 13:41, Kinglong Mee wrote:
>> When the first time pynfs runs after rpc/nfsd startup, always get the warning,
>>
>> Got error: Connection closed
>>
>> Commit 778620364ef5 "sunrpc/cache: make cache flushing more reliable." lets
>> cache_is_expired() checking expired as,
>>
>> return (h->expiry_time < seconds_since_boot()) ||
>> (detail->flush_time >= h->last_refresh);
>>
>> The detail->flush_time is equal to h->last_refresh time, when the cache is
>> new created and then do the upcall immediately. So that, the cache will be
>> treated as expired and be cleaned when write_flush().
I found the problem is caused by,
1. A new startup of nfsd, rpc.mountd, etc,
2. A rpc request from client (pynfs test, or normal mounting),
3. An ip_map cache is created but invalid, so upcall to rpc.mountd,
4. rpc.mountd process the ip_map upcall, before write the valid data to nfsd,
do auth_reload(), and check_useipaddr(),
5. For the first time, old_use_ipaddr = -1, that cause a cache_flush,
6. The ip_map cache will be treat as expired and clean,
7. When rpc.mountd write the valid data to nfsd, a new ip_map is created
and updated, the cache_check of old ip_map(doing the upcall) will
return -ETIMEDOUT.
8. RPC layer return SVC_CLOSE and close the xprt after commit 4d712ef1db05
"svcauth_gss: Close connection when dropping an incoming message"
Although it is exist only one time, but I don't like the noise.
Is the cache_flush for old_use_ipaddr = -1 necessary in step 5?
I have no idea about how to fix it, any suggests?
thanks,
Kinglong Mee
>>
>> This patch skips checking the pending cache expired when doing upcall.
>>
>> Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
>> ---
>> include/linux/sunrpc/cache.h | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
>> index 62a60ee..9961c1f 100644
>> --- a/include/linux/sunrpc/cache.h
>> +++ b/include/linux/sunrpc/cache.h
>> @@ -204,8 +204,11 @@ static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
>> kref_put(&h->ref, cd->cache_put);
>> }
>>
>> -static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
>> +static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h)
>> {
>> + if (test_bit(CACHE_PENDING, &h->flags))
>> + return false;
>> +
>
> Sorry, with this patch there is a bug exist,
> When a pending cache exist, sunrpc_destroy_cache_detail() cann't
> cleanup the cache_detail, but user always free it later,
> that will cause a NULL reference.
>
> Please ignore this patch, maybe another patch for the above problem
> will be sent.
>
> thanks,
> Kinglong Mee
>
>> return (h->expiry_time < seconds_since_boot()) ||
>> (detail->flush_time >= h->last_refresh);
>> }
>>
>
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