From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Wed, 30 Jul 2014 12:27:09 +0000 (-0400)
Subject: nfsd: Ensure lookup_clientid() takes client_lock
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3e339f964b74b7223ab128f36f4b2aaf9dc12eb9;p=linux-beck.git

nfsd: Ensure lookup_clientid() takes client_lock

Ensure that the client lookup is done safely under the client_lock, so
we're not relying on the client_mutex.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 68383b09c7dc..f9d077d800ee 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3451,13 +3451,17 @@ static __be32 lookup_clientid(clientid_t *clid,
 	 * will be false.
 	 */
 	WARN_ON_ONCE(cstate->session);
+	spin_lock(&nn->client_lock);
 	found = find_confirmed_client(clid, false, nn);
-	if (!found)
+	if (!found) {
+		spin_unlock(&nn->client_lock);
 		return nfserr_expired;
+	}
+	atomic_inc(&found->cl_refcount);
+	spin_unlock(&nn->client_lock);
 
 	/* Cache the nfs4_client in cstate! */
 	cstate->clp = found;
-	atomic_inc(&found->cl_refcount);
 	return nfs_ok;
 }