On Wed, 06 Aug 2014 21:35:40 +0800
Kinglong Mee <kinglongmee@xxxxxxxxx> wrote:
> Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
> ---
> 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@xxxxxxxxxx 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 <jlayton@xxxxxxxxxxxxxxx>
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