Re: [PATCH 1/3] NFSv4: Fix a slot leak in nfs40_sequence_done

[Chuck Lever <chuck.lever@oracle.com>]

On Jan 30, 2014, at 8:55 AM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:

> 
> On Jan 30, 2014, at 11:49, Chuck Lever <chuck.lever@oracle.com> wrote:
> 
>> 
>> On Jan 29, 2014, at 9:36 AM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:
>> 
>>> The check for whether or not we sent an RPC call in nfs40_sequence_done
>>> is insufficient to decide whether or not we are holding a session slot,
>>> and thus should not be used to decide when to free that slot.
>>> 
>>> This patch replaces the RPC_WAS_SENT() test with the correct test for
>>> whether or not slot == NULL.
>>> 
>>> Cc: Chuck Lever <chuck.lever@oracle.com>
>>> Cc: stable@vger.kernel.org # 3.12+
>>> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
>>> ---
>>> fs/nfs/nfs4proc.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>> 
>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>>> index ae00c3ed733f..493e9cce1f11 100644
>>> --- a/fs/nfs/nfs4proc.c
>>> +++ b/fs/nfs/nfs4proc.c
>>> @@ -539,7 +539,7 @@ static int nfs40_sequence_done(struct rpc_task *task,
>>> 	struct nfs4_slot *slot = res->sr_slot;
>>> 	struct nfs4_slot_table *tbl;
>>> 
>>> -	if (!RPC_WAS_SENT(task))
>>> +	if (slot == NULL)
>>> 		goto out;
>> 
>> When CONFIG_NFS_V4_1 is enabled, nfs4_sequence_done() already does the slot == NULL test, though the other nfs40_sequence_done() call sites do not.  This patch should clean that up?
> 
> Unfortunately we can’t touch nfs4_sequence_done: it wants to test for whether or not a NFSv4.1 session exists, which requires it to look at slot->table->session. :-(

Move the slot == NULL check to all nfs40_sequence_done() call sites?  <shrug>

If not, can we get a code comment that explains why that check is done twice in the common path?

--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com