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Commit 57bfa891 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Deal more correctly with duplicate delegations 



If a (broken?) server hands out two different delegations for the same
file, then we should return one of them.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 6f23e387

fs/nfs/delegation.c

+51 −38
Original line number Diff line number Diff line
@@ -125,6 +125,32 @@ void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, st 
	put_rpccred(oldcred);

}



static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)

{

	int res = 0;



	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);

	nfs_free_delegation(delegation);

	return res;

}



static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)

{

	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);



	if (delegation == NULL)

		goto nomatch;

	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,

				sizeof(delegation->stateid.data)) != 0)

		goto nomatch;

	list_del_rcu(&delegation->super_list);

	nfsi->delegation_state = 0;

	rcu_assign_pointer(nfsi->delegation, NULL);

	return delegation;

nomatch:

	return NULL;

}



/*

 * Set up a delegation on an inode

 */
@@ -133,6 +159,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct 
	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs_delegation *delegation;

	struct nfs_delegation *freeme = NULL;

	int status = 0;



	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
@@ -147,42 +174,45 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct 
	delegation->inode = inode;



	spin_lock(&clp->cl_lock);

	if (rcu_dereference(nfsi->delegation) == NULL) {

		list_add_rcu(&delegation->super_list, &clp->cl_delegations);

		nfsi->delegation_state = delegation->type;

		rcu_assign_pointer(nfsi->delegation, delegation);

		delegation = NULL;

	} else {

	if (rcu_dereference(nfsi->delegation) != NULL) {

		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,

					sizeof(delegation->stateid)) != 0 ||

				delegation->type != nfsi->delegation->type) {

			printk(KERN_WARNING "%s: server %s handed out "

					sizeof(delegation->stateid)) == 0 &&

				delegation->type == nfsi->delegation->type) {

			goto out;

		}

		/*

		 * Deal with broken servers that hand out two

		 * delegations for the same file.

		 */

		dfprintk(FILE, "%s: server %s handed out "

				"a duplicate delegation!\n",

				__FUNCTION__, clp->cl_hostname);

			status = -EIO;

		if (delegation->type <= nfsi->delegation->type) {

			freeme = delegation;

			delegation = NULL;

			goto out;

		}

		freeme = nfs_detach_delegation_locked(nfsi, NULL);

	}

	list_add_rcu(&delegation->super_list, &clp->cl_delegations);

	nfsi->delegation_state = delegation->type;

	rcu_assign_pointer(nfsi->delegation, delegation);

	delegation = NULL;



	/* Ensure we revalidate the attributes and page cache! */

	spin_lock(&inode->i_lock);

	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;

	spin_unlock(&inode->i_lock);



out:

	spin_unlock(&clp->cl_lock);

	if (delegation != NULL)

		nfs_free_delegation(delegation);

	if (freeme != NULL)

		nfs_do_return_delegation(inode, freeme, 0);

	return status;

}



static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)

{

	int res = 0;



	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);

	nfs_free_delegation(delegation);

	return res;

}



/* Sync all data to disk upon delegation return */

static void nfs_msync_inode(struct inode *inode)

{
@@ -211,23 +241,6 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat 
	return nfs_do_return_delegation(inode, delegation, 1);

}



static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)

{

	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);



	if (delegation == NULL)

		goto nomatch;

	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,

				sizeof(delegation->stateid.data)) != 0)

		goto nomatch;

	list_del_rcu(&delegation->super_list);

	nfsi->delegation_state = 0;

	rcu_assign_pointer(nfsi->delegation, NULL);

	return delegation;

nomatch:

	return NULL;

}



/*

 * This function returns the delegation without reclaiming opens

 * or protecting against delegation reclaims.