From cf6726e2ee387b0eff303628eaa0beaf36a1aeb4 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 19 Dec 2014 11:22:28 -0500 Subject: [PATCH] NFSv4: Deal with atomic upgrades of an existing delegation 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 | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index 7f3f60641344..16b754ee0d09 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -301,6 +301,17 @@ nfs_inode_detach_delegation(struct inode *inode) return nfs_detach_delegation(nfsi, delegation, server); } +static void +nfs_update_inplace_delegation(struct nfs_delegation *delegation, + const struct nfs_delegation *update) +{ + if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) { + delegation->stateid.seqid = update->stateid.seqid; + smp_wmb(); + delegation->type = update->type; + } +} + /** * nfs_inode_set_delegation - set up a delegation on an inode * @inode: inode to which delegation applies @@ -334,9 +345,12 @@ 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(old_delegation, + delegation); + nfsi->delegation_state = old_delegation->type; goto out; } /* -- 2.20.1