Merge tag 'regmap-3.4' into regmap-stride

regmap: Last minute bug fix for 3.4

This is a last minute bug fix that was only just noticed since the code
path that's being exercised here is one that is fairly rarely used.  The
changelog for the change itself is extremely clear and the code itself
is obvious to inspection so should be pretty safe.

Conflicts:
	drivers/base/regmap/regmap.c (overlap between the fix and stride code)

1 files changed, 19 insertions, 12 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 0f43414eb25..7f0fcfc1fe9 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -393,6 +393,7 @@ nfs4_remove_state_owner_locked(struct nfs4_state_owner *sp)
 static void
 nfs4_init_seqid_counter(struct nfs_seqid_counter *sc)
 {
+	sc->create_time = ktime_get();
 	sc->flags = 0;
 	sc->counter = 0;
 	spin_lock_init(&sc->lock);
@@ -434,13 +435,17 @@ nfs4_alloc_state_owner(struct nfs_server *server,
 static void
 nfs4_drop_state_owner(struct nfs4_state_owner *sp)
 {
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
+	struct rb_node *rb_node = &sp->so_server_node;
+
+	if (!RB_EMPTY_NODE(rb_node)) {
 		struct nfs_server *server = sp->so_server;
 		struct nfs_client *clp = server->nfs_client;
 
 		spin_lock(&clp->cl_lock);
-		rb_erase(&sp->so_server_node, &server->state_owners);
-		RB_CLEAR_NODE(&sp->so_server_node);
+		if (!RB_EMPTY_NODE(rb_node)) {
+			rb_erase(rb_node, &server->state_owners);
+			RB_CLEAR_NODE(rb_node);
+		}
 		spin_unlock(&clp->cl_lock);
 	}
 }
@@ -516,6 +521,14 @@ out:
 /**
  * nfs4_put_state_owner - Release a nfs4_state_owner
  * @sp: state owner data to release
+ *
+ * Note that we keep released state owners on an LRU
+ * list.
+ * This caches valid state owners so that they can be
+ * reused, to avoid the OPEN_CONFIRM on minor version 0.
+ * It also pins the uniquifier of dropped state owners for
+ * a while, to ensure that those state owner names are
+ * never reused.
  */
 void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 {
@@ -525,15 +538,9 @@ void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 	if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
 		return;
 
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
-		sp->so_expires = jiffies;
-		list_add_tail(&sp->so_lru, &server->state_owners_lru);
-		spin_unlock(&clp->cl_lock);
-	} else {
-		nfs4_remove_state_owner_locked(sp);
-		spin_unlock(&clp->cl_lock);
-		nfs4_free_state_owner(sp);
-	}
+	sp->so_expires = jiffies;
+	list_add_tail(&sp->so_lru, &server->state_owners_lru);
+	spin_unlock(&clp->cl_lock);
 }
 
 /**