Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ie0-f179.google.com ([209.85.223.179]:33981 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751529AbaLSSwr (ORCPT ); Fri, 19 Dec 2014 13:52:47 -0500 Received: by mail-ie0-f179.google.com with SMTP id rp18so1259438iec.10 for ; Fri, 19 Dec 2014 10:52:46 -0800 (PST) From: Trond Myklebust To: Olga Kornievskaia Cc: linux-nfs Subject: [PATCH v2 1/2] NFSv4: Deal with atomic upgrades of an existing delegation Date: Fri, 19 Dec 2014 13:52:33 -0500 Message-Id: <1419015154-91037-1-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org List-ID: Ensure that we deal correctly with the case where the server sends us a newer instance of the same delegation. If the stateids match, but the sequence numbers differ, then treat the new delegation as if it were an atomic upgrade. Signed-off-by: Trond Myklebust --- fs/nfs/delegation.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index 7f3f60641344..02b5b2a6d557 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -301,6 +301,19 @@ nfs_inode_detach_delegation(struct inode *inode) return nfs_detach_delegation(nfsi, delegation, server); } +static void +nfs_update_inplace_delegation(struct nfs_inode *nfsi, + struct nfs_delegation *delegation, + struct nfs_delegation *update) +{ + if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) + return; + delegation->stateid.seqid = update->stateid.seqid; + smp_wmb(); + delegation->type = update->type; + nfsi->delegation_state = update->type; +} + /** * nfs_inode_set_delegation - set up a delegation on an inode * @inode: inode to which delegation applies @@ -334,9 +347,11 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct old_delegation = rcu_dereference_protected(nfsi->delegation, lockdep_is_held(&clp->cl_lock)); if (old_delegation != NULL) { - if (nfs4_stateid_match(&delegation->stateid, - &old_delegation->stateid) && - delegation->type == old_delegation->type) { + /* Is this an update of the existing delegation? */ + if (nfs4_stateid_match_other(&old_delegation->stateid, + &delegation->stateid)) { + nfs_update_inplace_delegation(nfsi, old_delegation, + delegation); goto out; } /* -- 2.1.0