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Commit cf6726e2 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

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

fs/nfs/delegation.c

+17 −3
Original line number Diff line number Diff line
@@ -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;

		}

		/*