NFSv4: Retry CLOSE and DELEGRETURN on NFS4ERR_OLD_STATEID.

If we're racing with an OPEN, then retry the operation instead of
declaring it a success.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
[Andrew W Elble: Fix a typo in nfs4_refresh_open_stateid]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 6e3f37288348..cee1e000b41e 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -986,6 +986,22 @@ out:
 	return ret;
 }
 
+bool nfs4_refresh_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
+{
+	bool ret;
+	int seq;
+
+	do {
+		ret = false;
+		seq = read_seqbegin(&state->seqlock);
+		if (nfs4_state_match_open_stateid_other(state, dst)) {
+			dst->seqid = state->open_stateid.seqid;
+			ret = true;
+		}
+	} while (read_seqretry(&state->seqlock, seq));
+	return ret;
+}
+
 static void nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
 {
 	const nfs4_stateid *src;