Commit cf6726e2 authored by Trond Myklebust's avatar Trond Myklebust

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: default avatarTrond Myklebust <Trond.Myklebust@primarydata.com>
parent 89f0ff38
......@@ -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;
}
/*
......
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