Re: [PATCH 3/3 v2] NFSD: Increase the reference of lockowner when coping file_lock

[Kinglong Mee <kinglongmee@gmail.com>]

On 8/12/2014 00:46, Jeff Layton wrote:
> On Sun, 10 Aug 2014 23:43:57 +0800
> Kinglong Mee <kinglongmee@gmail.com> wrote:
> 
>> v2: Fix bad using of struct file_lock_operations for handle the owner.
>>
>> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
>> ---
>>  fs/nfsd/nfs4state.c | 32 ++++++++++++++++++++++++++++++--
>>  1 file changed, 30 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 2e80a59..24a8d91 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4867,9 +4867,33 @@ nfs4_transform_lock_offset(struct file_lock *lock)
>>  		lock->fl_end = OFFSET_MAX;
>>  }
>>  
>> +static inline struct nfs4_lockowner *get_lockowner(struct nfs4_lockowner *lo)
>> +{
>> +	atomic_inc(&lo->lo_owner.so_count);
>> +	return lo;
>> +}
>> +
> 
> The other places that increment the so_count on a lockowner should
> probably be changed to use get_lockowner.

Got it, thanks.

> 
> Or what may be better is to make a nfs4_get_stateowner call and change
> all of the places that bump the so_count to use it. Then you could just
> do something like this in the right spot below:
> 
>     file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(lock_sop));

Yes, nfs4_get_stateowner corresponds with nfs4_put_stateowner.

>> +static void nfsd4_fl_copy_owner(struct file_lock *dst, struct file_lock *src)
>> +{
>> +	struct nfs4_lockowner *lo = (struct nfs4_lockowner *) src->fl_owner;
>> +	dst->fl_owner = (fl_owner_t) get_lockowner(lo);
>> +}
>> +
>> +static void nfsd4_fl_release_owner(struct file_lock *fl)
>> +{
>> +	struct nfs4_lockowner *lo = (struct nfs4_lockowner *) fl->fl_owner;
>> +
>> +	if (lo) {
>> +		nfs4_put_stateowner(&lo->lo_owner);
>> +		fl->fl_owner = NULL;
>> +	}
>> +}
>> +
>>  /* Hack!: For now, we're defining this just so we can use a pointer to it
>>   * as a unique cookie to identify our (NFSv4's) posix locks. */
> 
> The above comment should be removed now.

OK, will remove it in next version.

thanks,
Kinglong Mee

> 
>>  static const struct lock_manager_operations nfsd_posix_mng_ops  = {
>> +	.lm_copy_owner = nfsd4_fl_copy_owner,
>> +	.lm_release_owner = nfsd4_fl_release_owner,
>>  };
>>  
>>  static inline void
>> @@ -5238,7 +5262,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>  		status = nfserr_openmode;
>>  		goto out;
>>  	}
>> -	file_lock->fl_owner = (fl_owner_t)lock_sop;
>> +
>> +	file_lock->fl_owner = (fl_owner_t)get_lockowner(lock_sop);
>>  	file_lock->fl_pid = current->tgid;
>>  	file_lock->fl_file = filp;
>>  	file_lock->fl_flags = FL_POSIX;
>> @@ -5405,6 +5430,7 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>  	struct nfs4_ol_stateid *stp;
>>  	struct file *filp = NULL;
>>  	struct file_lock *file_lock = NULL;
>> +	struct nfs4_lockowner *lock_sop = NULL;
>>  	__be32 status;
>>  	int err;
>>  	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
>> @@ -5426,6 +5452,8 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>  		status = nfserr_lock_range;
>>  		goto put_stateid;
>>  	}
>> +
>> +	lock_sop = lockowner(stp->st_stateowner);
>>  	file_lock = locks_alloc_lock();
>>  	if (!file_lock) {
>>  		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
>> @@ -5434,7 +5462,7 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>  	}
>>  	locks_init_lock(file_lock);
>>  	file_lock->fl_type = F_UNLCK;
>> -	file_lock->fl_owner = (fl_owner_t)lockowner(stp->st_stateowner);
>> +	file_lock->fl_owner = (fl_owner_t)get_lockowner(lock_sop);
>>  	file_lock->fl_pid = current->tgid;
>>  	file_lock->fl_file = filp;
>>  	file_lock->fl_flags = FL_POSIX;
> 
>