From: Anna Schumaker <Anna.Schumaker@netapp.com>
Date: Wed, 3 Sep 2014 18:15:40 +0000 (-0400)
Subject: NFS: Clear up state owner lock usage
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=61beef75cc5bae119e500c9f25daad8596c7cbe4;p=openwrt%2Fstaging%2Fblogic.git

NFS: Clear up state owner lock usage

can_open_cached() reads values out of the state structure, meaning that
we need the so_lock to have a correct return value.  As a bonus, this
helps clear up some potentially confusing code.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 7dd8aca31c29..18eb31c1ea0b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1307,15 +1307,13 @@ static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
 	int ret = -EAGAIN;
 
 	for (;;) {
+		spin_lock(&state->owner->so_lock);
 		if (can_open_cached(state, fmode, open_mode)) {
-			spin_lock(&state->owner->so_lock);
-			if (can_open_cached(state, fmode, open_mode)) {
-				update_open_stateflags(state, fmode);
-				spin_unlock(&state->owner->so_lock);
-				goto out_return_state;
-			}
+			update_open_stateflags(state, fmode);
 			spin_unlock(&state->owner->so_lock);
+			goto out_return_state;
 		}
+		spin_unlock(&state->owner->so_lock);
 		rcu_read_lock();
 		delegation = rcu_dereference(nfsi->delegation);
 		if (!can_open_delegated(delegation, fmode)) {