Re: [PATCH 5/5] lockd: Remove unneeded initialization of file_lock::c.flc_flags

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

> On Oct 17, 2024, at 3:13 PM, Jeff Layton <jlayton@kernel.org> wrote:
> 
> On Thu, 2024-10-17 at 09:36 -0400, cel@kernel.org wrote:
>> From: Chuck Lever <chuck.lever@oracle.com>
>> 
>> Since commit 75c7940d2a86 ("lockd: set missing fl_flags field when
>> retrieving args"), nlmsvc_retrieve_args() initializes the flc_flags
>> field. svcxdr_decode_lock() no longer needs to do this.
>> 
>> This clean up removes one dependency on the nlm_lock:fl field. No
>> behavior change is expected.
>> 
>> Analysis:
>> 
>> svcxdr_decode_lock() is called by:
>> 
>> nlm4svc_decode_testargs()
>> nlm4svc_decode_lockargs()
>> nlm4svc_decode_cancargs()
>> nlm4svc_decode_unlockargs()
>> 
>> nlm4svc_decode_testargs() is used by:
>> - NLMPROC4_TEST and NLMPROC4_TEST_MSG, which call nlmsvc_retrieve_args()
>> - NLMPROC4_GRANTED and NLMPROC4_GRANTED_MSG, which don't pass the
>>  lock's file_lock to the generic lock API
>> 
>> nlm4svc_decode_lockargs() is used by:
>> - NLMPROC4_LOCK and NLM4PROC4_LOCK_MSG, which call nlmsvc_retrieve_args()
>> - NLMPROC4_UNLOCK and NLM4PROC4_UNLOCK_MSG, which call nlmsvc_retrieve_args()
>> - NLMPROC4_NM_LOCK, which calls nlmsvc_retrieve_args()
>> 
>> nlm4svc_decode_cancargs() is used by:
>> - NLMPROC4_CANCEL and NLMPROC4_CANCEL_MSG, which call nlmsvc_retrieve_args()
>> 
>> nlm4svc_decode_unlockargs() is used by:
>> - NLMPROC4_UNLOCK and NLMPROC4_UNLOCK_MSG, which call nlmsvc_retrieve_args()
>> 
>> All callers except GRANTED/GRANTED_MSG eventually call
>> nlmsvc_retrieve_args() before using nlm_lock::fl.c.flc_flags. Thus
>> this change is safe.
>> 
>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> ---
>> fs/lockd/svc4proc.c | 5 +++--
>> fs/lockd/xdr4.c     | 1 -
>> 2 files changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
>> index 2cb603013111..109e5caae8c7 100644
>> --- a/fs/lockd/svc4proc.c
>> +++ b/fs/lockd/svc4proc.c
>> @@ -46,14 +46,15 @@ nlm4svc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
>> if (filp != NULL) {
>> int mode = lock_to_openmode(&lock->fl);
>> 
>> + lock->fl.c.flc_flags = FL_POSIX;
>> +
>> error = nlm_lookup_file(rqstp, &file, lock);
>> if (error)
>> goto no_locks;
>> *filp = file;
>> 
>> /* Set up the missing parts of the file_lock structure */
>> - lock->fl.c.flc_flags = FL_POSIX;
>> - lock->fl.c.flc_file  = file->f_file[mode];
>> + lock->fl.c.flc_file = file->f_file[mode];
>> lock->fl.c.flc_pid = current->tgid;
>> lock->fl.fl_start = (loff_t)lock->lock_start;
>> lock->fl.fl_end = lock->lock_len ?
>> diff --git a/fs/lockd/xdr4.c b/fs/lockd/xdr4.c
>> index 60466b8bac58..e343c820301f 100644
>> --- a/fs/lockd/xdr4.c
>> +++ b/fs/lockd/xdr4.c
>> @@ -89,7 +89,6 @@ svcxdr_decode_lock(struct xdr_stream *xdr, struct nlm_lock *lock)
>> return false;
>> 
>> locks_init_lock(fl);
>> - fl->c.flc_flags = FL_POSIX;
>> fl->c.flc_type  = F_RDLCK;
>> nlm4svc_set_file_lock_range(fl, lock->lock_start, lock->lock_len);
>> return true;
> 
> 1-4 look fine. You can add my R-b to those.

Thanks!


> For this one, I think I'd rather see this go the other way, and just
> eliminate the setting of flc_flags in nlm4svc_retrieve_args. We only
> deal with FL_POSIX locks in svc lockd, and that does it right after
> locks_init_lock, so I think that means it'll be done earlier, no?

Have a look at the nlm4 branch in my kernel.org <http://kernel.org/> repo to see where
this is headed.


> Also, I think the same duplication is in nlmsvc_retrieve_args and the
> nlmv3 version of svcxdr_decode_lock.

Which is going away when NFSv2 is removed. I'm not too concerned
about that duplication.


--
Chuck Lever