Re: [PATCH 2/2] NFSD: Re-initialize fh_post/pre_saved between two operations

[Kinglong Mee <kinglongmee@gmail.com>]

于 2014/3/29 05:19, J. Bruce Fields 写道:
> On Wed, Mar 26, 2014 at 05:12:09PM +0800, Kinglong Mee wrote:
>> Testing NFS4.0 by pynfs, I got some messeages as,
>> "nfsd: inode locked twice during operation."
>
> Thanks for looking into this.  I agree that we should clear fh_pre_saved
> and fh_post_saved between compound ops.
>
> This is kind of non-obvious, though, so I think it would be worth moving
> these two assignments to a little helper function (how about
> "fh_clear_wcc_data()" for a name?) and adding a comment with the
> definition of the function, explaining why we need it.

That's great.
Thanks for your advice.

>
>> When one compound RPC contains two or more SETATTR operation
>> for one filehandle,the second SETATTR will cause the message.
>
> Also worth noting that this affects any op that locks the filehandle
> (e.g. a compound with two LINK ops would probably trigger the same
> warning.)

Yes, that's right.

Thanks,
Kinglong Mee

>
> --b.
>
>>
>> Because after the first SETATTR, nfsd will not call fh_put()
>> to release current filehandle, it means filehandle have unlocked
>> with fh_post_saved = 1.
>> The second SETATTR find fh_post_saved = 1, and printk the message.
>>
>> This patch re-initialize fh_post/pre_saved between two operations.
>>
>> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
>> ---
>>   fs/nfsd/nfs4proc.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 550faf2..103d1ac 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1356,6 +1356,9 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
>>   			  !(opdesc->op_flags & ALLOWED_ON_ABSENT_FS)) {
>>   			op->status = nfserr_moved;
>>   			goto encode_op;
>> +		} else {
>> +			current_fh->fh_post_saved = 0;
>> +			current_fh->fh_pre_saved = 0;
>>   		}
>>
>>   		/* If op is non-idempotent */
>> --
>> 1.8.5.3
>>
>