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

On 8/12/2014 00:46, Jeff Layton wrote:

On Sun, 10 Aug 2014 23:43:57 +0800
Kinglong Mee [off-list ref] wrote:

quoted

v2: Fix bad using of struct file_lock_operations for handle the owner.

Signed-off-by: Kinglong Mee <redacted>
---
 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.

quoted

+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

quoted

 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;