[PATCH] NFSv4: Clean up nfs4 lock state accounting

 Ensure that lock owner structures are not released prematurely.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 112 insertions, 144 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 7c6f1d6..ec1a22d 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -128,6 +128,7 @@ struct nfs4_state_owner {
 
 struct nfs4_lock_state {
 	struct list_head	ls_locks;	/* Other lock stateids */
+	struct nfs4_state *	ls_state;	/* Pointer to open state */
 	fl_owner_t		ls_owner;	/* POSIX lock owner */
 #define NFS_LOCK_INITIALIZED 1
 	int			ls_flags;
@@ -153,7 +154,7 @@ struct nfs4_state {
 
 	unsigned long flags;		/* Do we hold any locks? */
 	struct semaphore lock_sema;	/* Serializes file locking operations */
-	rwlock_t state_lock;		/* Protects the lock_states list */
+	spinlock_t state_lock;		/* Protects the lock_states list */
 
 	nfs4_stateid stateid;
 
@@ -225,12 +226,8 @@ extern void nfs4_close_state(struct nfs4_state *, mode_t);
 extern struct nfs4_state *nfs4_find_state(struct inode *, struct rpc_cred *, mode_t mode);
 extern void nfs4_increment_seqid(int status, struct nfs4_state_owner *sp);
 extern void nfs4_schedule_state_recovery(struct nfs4_client *);
-extern struct nfs4_lock_state *nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t);
-extern struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t);
-extern void nfs4_put_lock_state(struct nfs4_lock_state *state);
+extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
 extern void nfs4_increment_lock_seqid(int status, struct nfs4_lock_state *ls);
-extern void nfs4_notify_setlk(struct nfs4_state *, struct file_lock *, struct nfs4_lock_state *);
-extern void nfs4_notify_unlck(struct nfs4_state *, struct file_lock *, struct nfs4_lock_state *);
 extern void nfs4_copy_stateid(nfs4_stateid *, struct nfs4_state *, fl_owner_t);
 
 extern const nfs4_stateid zero_stateid;
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index af80b59..0ddc201 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2626,14 +2626,11 @@ static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock
 	down_read(&clp->cl_sem);
 	nlo.clientid = clp->cl_clientid;
 	down(&state->lock_sema);
-	lsp = nfs4_find_lock_state(state, request->fl_owner);
-	if (lsp)
-		nlo.id = lsp->ls_id; 
-	else {
-		spin_lock(&clp->cl_lock);
-		nlo.id = nfs4_alloc_lockowner_id(clp);
-		spin_unlock(&clp->cl_lock);
-	}
+	status = nfs4_set_lock_state(state, request);
+	if (status != 0)
+		goto out;
+	lsp = request->fl_u.nfs4_fl.owner;
+	nlo.id = lsp->ls_id; 
 	arg.u.lockt = &nlo;
 	status = rpc_call_sync(server->client, &msg, 0);
 	if (!status) {
@@ -2654,8 +2651,7 @@ static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock
 		request->fl_pid = 0;
 		status = 0;
 	}
-	if (lsp)
-		nfs4_put_lock_state(lsp);
+out:
 	up(&state->lock_sema);
 	up_read(&clp->cl_sem);
 	return status;
@@ -2715,28 +2711,26 @@ static int _nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock
 	};
 	struct nfs4_lock_state *lsp;
 	struct nfs_locku_opargs luargs;
-	int status = 0;
+	int status;
 			
 	down_read(&clp->cl_sem);
 	down(&state->lock_sema);
-	lsp = nfs4_find_lock_state(state, request->fl_owner);
-	if (!lsp)
+	status = nfs4_set_lock_state(state, request);
+	if (status != 0)
 		goto out;
+	lsp = request->fl_u.nfs4_fl.owner;
 	/* We might have lost the locks! */
-	if ((lsp->ls_flags & NFS_LOCK_INITIALIZED) != 0) {
-		luargs.seqid = lsp->ls_seqid;
-		memcpy(&luargs.stateid, &lsp->ls_stateid, sizeof(luargs.stateid));
-		arg.u.locku = &luargs;
-		status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
-		nfs4_increment_lock_seqid(status, lsp);
-	}
+	if ((lsp->ls_flags & NFS_LOCK_INITIALIZED) == 0)
+		goto out;
+	luargs.seqid = lsp->ls_seqid;
+	memcpy(&luargs.stateid, &lsp->ls_stateid, sizeof(luargs.stateid));
+	arg.u.locku = &luargs;
+	status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
+	nfs4_increment_lock_seqid(status, lsp);
 
-	if (status == 0) {
+	if (status == 0)
 		memcpy(&lsp->ls_stateid,  &res.u.stateid, 
 				sizeof(lsp->ls_stateid));
-		nfs4_notify_unlck(state, request, lsp);
-	}
-	nfs4_put_lock_state(lsp);
 out:
 	up(&state->lock_sema);
 	if (status == 0)
@@ -2762,7 +2756,7 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *r
 {
 	struct inode *inode = state->inode;
 	struct nfs_server *server = NFS_SERVER(inode);
-	struct nfs4_lock_state *lsp;
+	struct nfs4_lock_state *lsp = request->fl_u.nfs4_fl.owner;
 	struct nfs_lockargs arg = {
 		.fh = NFS_FH(inode),
 		.type = nfs4_lck_type(cmd, request),
@@ -2784,9 +2778,6 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *r
 	};
 	int status;
 
-	lsp = nfs4_get_lock_state(state, request->fl_owner);
-	if (lsp == NULL)
-		return -ENOMEM;
 	if (!(lsp->ls_flags & NFS_LOCK_INITIALIZED)) {
 		struct nfs4_state_owner *owner = state->owner;
 		struct nfs_open_to_lock otl = {
@@ -2808,27 +2799,26 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *r
 		* seqid mutating errors */
 		nfs4_increment_seqid(status, owner);
 		up(&owner->so_sema);
+		if (status == 0) {
+			lsp->ls_flags |= NFS_LOCK_INITIALIZED;
+			lsp->ls_seqid++;
+		}
 	} else {
 		struct nfs_exist_lock el = {
 			.seqid = lsp->ls_seqid,
 		};
 		memcpy(&el.stateid, &lsp->ls_stateid, sizeof(el.stateid));
 		largs.u.exist_lock = ⪙
-		largs.new_lock_owner = 0;
 		arg.u.lock = &largs;
 		status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
+		/* increment seqid on success, and * seqid mutating errors*/
+		nfs4_increment_lock_seqid(status, lsp);
 	}
-	/* increment seqid on success, and * seqid mutating errors*/
-	nfs4_increment_lock_seqid(status, lsp);
 	/* save the returned stateid. */
-	if (status == 0) {
+	if (status == 0)
 		memcpy(&lsp->ls_stateid, &res.u.stateid, sizeof(nfs4_stateid));
-		lsp->ls_flags |= NFS_LOCK_INITIALIZED;
-		if (!reclaim)
-			nfs4_notify_setlk(state, request, lsp);
-	} else if (status == -NFS4ERR_DENIED)
+	else if (status == -NFS4ERR_DENIED)
 		status = -EAGAIN;
-	nfs4_put_lock_state(lsp);
 	return status;
 }
 
@@ -2869,7 +2859,9 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
 
 	down_read(&clp->cl_sem);
 	down(&state->lock_sema);
-	status = _nfs4_do_setlk(state, cmd, request, 0);
+	status = nfs4_set_lock_state(state, request);
+	if (status == 0)
+		status = _nfs4_do_setlk(state, cmd, request, 0);
 	up(&state->lock_sema);
 	if (status == 0) {
 		/* Note: we always want to sleep here! */
@@ -2927,7 +2919,6 @@ nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request)
 		if (signalled())
 			break;
 	} while(status < 0);
-
 	return status;
 }
 
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 591ad1d..afe587d 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -360,7 +360,7 @@ nfs4_alloc_open_state(void)
 	atomic_set(&state->count, 1);
 	INIT_LIST_HEAD(&state->lock_states);
 	init_MUTEX(&state->lock_sema);
-	rwlock_init(&state->state_lock);
+	spin_lock_init(&state->state_lock);
 	return state;
 }
 
@@ -542,16 +542,6 @@ __nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 	return NULL;
 }
 
-struct nfs4_lock_state *
-nfs4_find_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
-{
-	struct nfs4_lock_state *lsp;
-	read_lock(&state->state_lock);
-	lsp = __nfs4_find_lock_state(state, fl_owner);
-	read_unlock(&state->state_lock);
-	return lsp;
-}
-
 /*
  * Return a compatible lock_state. If no initialized lock_state structure
  * exists, return an uninitialized one.
@@ -568,14 +558,13 @@ static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, f
 		return NULL;
 	lsp->ls_flags = 0;
 	lsp->ls_seqid = 0;	/* arbitrary */
-	lsp->ls_id = -1; 
 	memset(lsp->ls_stateid.data, 0, sizeof(lsp->ls_stateid.data));
 	atomic_set(&lsp->ls_count, 1);
 	lsp->ls_owner = fl_owner;
-	INIT_LIST_HEAD(&lsp->ls_locks);
 	spin_lock(&clp->cl_lock);
 	lsp->ls_id = nfs4_alloc_lockowner_id(clp);
 	spin_unlock(&clp->cl_lock);
+	INIT_LIST_HEAD(&lsp->ls_locks);
 	return lsp;
 }
 
@@ -585,121 +574,112 @@ static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, f
  *
  * The caller must be holding state->lock_sema and clp->cl_sem
  */
-struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
+static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
 {
-	struct nfs4_lock_state * lsp;
+	struct nfs4_lock_state *lsp, *new = NULL;
 	
-	lsp = nfs4_find_lock_state(state, owner);
-	if (lsp == NULL)
-		lsp = nfs4_alloc_lock_state(state, owner);
+	for(;;) {
+		spin_lock(&state->state_lock);
+		lsp = __nfs4_find_lock_state(state, owner);
+		if (lsp != NULL)
+			break;
+		if (new != NULL) {
+			new->ls_state = state;
+			list_add(&new->ls_locks, &state->lock_states);
+			set_bit(LK_STATE_IN_USE, &state->flags);
+			lsp = new;
+			new = NULL;
+			break;
+		}
+		spin_unlock(&state->state_lock);
+		new = nfs4_alloc_lock_state(state, owner);
+		if (new == NULL)
+			return NULL;
+	}
+	spin_unlock(&state->state_lock);
+	kfree(new);
 	return lsp;
 }
 
 /*
- * Byte-range lock aware utility to initialize the stateid of read/write
- * requests.
+ * Release reference to lock_state, and free it if we see that
+ * it is no longer in use
  */
-void
-nfs4_copy_stateid(nfs4_stateid *dst, struct nfs4_state *state, fl_owner_t fl_owner)
+static void nfs4_put_lock_state(struct nfs4_lock_state *lsp)
 {
-	if (test_bit(LK_STATE_IN_USE, &state->flags)) {
-		struct nfs4_lock_state *lsp;
+	struct nfs4_state *state;
 
-		lsp = nfs4_find_lock_state(state, fl_owner);
-		if (lsp) {
-			memcpy(dst, &lsp->ls_stateid, sizeof(*dst));
-			nfs4_put_lock_state(lsp);
-			return;
-		}
-	}
-	memcpy(dst, &state->stateid, sizeof(*dst));
+	if (lsp == NULL)
+		return;
+	state = lsp->ls_state;
+	if (!atomic_dec_and_lock(&lsp->ls_count, &state->state_lock))
+		return;
+	list_del(&lsp->ls_locks);
+	if (list_empty(&state->lock_states))
+		clear_bit(LK_STATE_IN_USE, &state->flags);
+	spin_unlock(&state->state_lock);
+	kfree(lsp);
 }
 
-/*
-* Called with state->lock_sema and clp->cl_sem held.
-*/
-void nfs4_increment_lock_seqid(int status, struct nfs4_lock_state *lsp)
+static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
 {
-	if (status == NFS_OK || seqid_mutating_err(-status))
-		lsp->ls_seqid++;
-}
+	struct nfs4_lock_state *lsp = src->fl_u.nfs4_fl.owner;
 
-/* 
-* Check to see if the request lock (type FL_UNLK) effects the fl lock.
-*
-* fl and request must have the same posix owner
-*
-* return: 
-* 0 -> fl not effected by request
-* 1 -> fl consumed by request
-*/
+	dst->fl_u.nfs4_fl.owner = lsp;
+	atomic_inc(&lsp->ls_count);
+}
 
-static int
-nfs4_check_unlock(struct file_lock *fl, struct file_lock *request)
+static void nfs4_fl_release_lock(struct file_lock *fl)
 {
-	if (fl->fl_start >= request->fl_start && fl->fl_end <= request->fl_end)
-		return 1;
-	return 0;
+	nfs4_put_lock_state(fl->fl_u.nfs4_fl.owner);
 }
 
-/*
- * Post an initialized lock_state on the state->lock_states list.
- */
-void nfs4_notify_setlk(struct nfs4_state *state, struct file_lock *request, struct nfs4_lock_state *lsp)
+static struct file_lock_operations nfs4_fl_lock_ops = {
+	.fl_copy_lock = nfs4_fl_copy_lock,
+	.fl_release_private = nfs4_fl_release_lock,
+};
+
+int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
 {
-	if (!list_empty(&lsp->ls_locks))
-		return;
-	atomic_inc(&lsp->ls_count);
-	write_lock(&state->state_lock);
-	list_add(&lsp->ls_locks, &state->lock_states);
-	set_bit(LK_STATE_IN_USE, &state->flags);
-	write_unlock(&state->state_lock);
+	struct nfs4_lock_state *lsp;
+
+	if (fl->fl_ops != NULL)
+		return 0;
+	lsp = nfs4_get_lock_state(state, fl->fl_owner);
+	if (lsp == NULL)
+		return -ENOMEM;
+	fl->fl_u.nfs4_fl.owner = lsp;
+	fl->fl_ops = &nfs4_fl_lock_ops;
+	return 0;
 }
 
-/* 
- * to decide to 'reap' lock state:
- * 1) search i_flock for file_locks with fl.lock_state = to ls.
- * 2) determine if unlock will consume found lock. 
- * 	if so, reap
- *
- * 	else, don't reap.
- *
+/*
+ * Byte-range lock aware utility to initialize the stateid of read/write
+ * requests.
  */
-void
-nfs4_notify_unlck(struct nfs4_state *state, struct file_lock *request, struct nfs4_lock_state *lsp)
+void nfs4_copy_stateid(nfs4_stateid *dst, struct nfs4_state *state, fl_owner_t fl_owner)
 {
-	struct inode *inode = state->inode;
-	struct file_lock *fl;
+	struct nfs4_lock_state *lsp;
 
-	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
-		if (!(fl->fl_flags & FL_POSIX))
-			continue;
-		if (fl->fl_owner != lsp->ls_owner)
-			continue;
-		/* Exit if we find at least one lock which is not consumed */
-		if (nfs4_check_unlock(fl,request) == 0)
-			return;
-	}
+	memcpy(dst, &state->stateid, sizeof(*dst));
+	if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
+		return;
 
-	write_lock(&state->state_lock);
-	list_del_init(&lsp->ls_locks);
-	if (list_empty(&state->lock_states))
-		clear_bit(LK_STATE_IN_USE, &state->flags);
-	write_unlock(&state->state_lock);
+	spin_lock(&state->state_lock);
+	lsp = __nfs4_find_lock_state(state, fl_owner);
+	if (lsp != NULL && (lsp->ls_flags & NFS_LOCK_INITIALIZED) != 0)
+		memcpy(dst, &lsp->ls_stateid, sizeof(*dst));
+	spin_unlock(&state->state_lock);
 	nfs4_put_lock_state(lsp);
 }
 
 /*
- * Release reference to lock_state, and free it if we see that
- * it is no longer in use
- */
-void
-nfs4_put_lock_state(struct nfs4_lock_state *lsp)
+* Called with state->lock_sema and clp->cl_sem held.
+*/
+void nfs4_increment_lock_seqid(int status, struct nfs4_lock_state *lsp)
 {
-	if (!atomic_dec_and_test(&lsp->ls_count))
-		return;
-	BUG_ON (!list_empty(&lsp->ls_locks));
-	kfree(lsp);
+	if (status == NFS_OK || seqid_mutating_err(-status))
+		lsp->ls_seqid++;
 }
 
 /*