Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qa0-f52.google.com ([209.85.216.52]:57781 "EHLO mail-qa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbaHILIV (ORCPT ); Sat, 9 Aug 2014 07:08:21 -0400 Received: by mail-qa0-f52.google.com with SMTP id j15so6285353qaq.25 for ; Sat, 09 Aug 2014 04:08:20 -0700 (PDT) From: Jeff Layton Date: Sat, 9 Aug 2014 07:08:18 -0400 To: Kinglong Mee Cc: "J. Bruce Fields" , Linux NFS Mailing List , Trond Myklebust , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 2/3] NFSD: Increase the reference of lockowner when coping file_lock Message-ID: <20140809070818.4d939a6a@tlielax.poochiereds.net> In-Reply-To: <53E22F2C.8070900@gmail.com> References: <53BAAAC5.9000106@gmail.com> <53E22EA5.70708@gmail.com> <53E22F2C.8070900@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, 06 Aug 2014 21:35:40 +0800 Kinglong Mee wrote: > Signed-off-by: Kinglong Mee > --- > fs/nfsd/nfs4state.c | 33 +++++++++++++++++++++++++++++++-- > 1 file changed, 31 insertions(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 24168ae..07e4b5c 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -4867,6 +4867,29 @@ 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; > +} > + > +static void nfsd4_fl_copy_lock(struct file_lock *dst, struct file_lock *src) > +{ > + struct nfs4_lockowner *lo = (struct nfs4_lockowner *) src->fl_owner; > + get_lockowner(lo); > +} > + > +static void nfsd4_fl_release_lock(struct file_lock *fl) > +{ > + struct nfs4_lockowner *lo = (struct nfs4_lockowner *) fl->fl_owner; > + nfs4_put_stateowner(&lo->lo_owner); > +} > + > +static const struct file_lock_operations nfsd4_fl_lock_ops = { > + .fl_copy_lock = nfsd4_fl_copy_lock, > + .fl_release_private = nfsd4_fl_release_lock, > +}; > + > static inline void > nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny) > { > @@ -5233,10 +5256,12 @@ 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 | FL_NFSD; > + file_lock->fl_ops = &nfsd4_fl_lock_ops; > file_lock->fl_start = lock->lk_offset; > file_lock->fl_end = last_byte_offset(lock->lk_offset, lock->lk_length); > nfs4_transform_lock_offset(file_lock); > @@ -5399,6 +5424,7 @@ 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); > @@ -5420,6 +5446,8 @@ 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__); > @@ -5428,10 +5456,11 @@ 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 | FL_NFSD; > + file_lock->fl_ops = &nfsd4_fl_lock_ops; > file_lock->fl_start = locku->lu_offset; > > file_lock->fl_end = last_byte_offset(locku->lu_offset, (Sorry I didn't respond to these before -- I no longer work for Red Hat, so emails to jlayton@redhat.com don't get to me). This looks really wrong. In this case, knfsd is acting as a (server-side) lock manager, not a filesystem: const struct file_lock_operations *fl_ops; /* Callbacks for filesystems */ const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */ So really, taking and putting of lockowner references is really the purview of the lockmanager. If you had a filesystem that set fl_ops and was exportable, then this will likely break it. The fact that the file locking code uses struct file_lock for lock requests and for tracking the locks themselves makes for a horribly confusing interface. If I were designing this from scratch I would have made those two distinct structures. Maybe we should do that anyway sometime. What you probably ought want to do is to declare some new fl_lmops for taking and putting lockowner references and add hooks to call them at the appropriate places. -- Jeff Layton