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Commit aac00a8d authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4: Check for the existence of a delegation in nfs4_open_prepare() 



We should not be calling open() on an inode that has a delegation unless
we're doing a reclaim.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 3e309914

fs/nfs/nfs4proc.c

+107 −88
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *) 
static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry);

static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);

static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs_client *clp);

static int _nfs4_do_access(struct inode *inode, struct rpc_cred *cred, int openflags);



/* Prevent leaks of NFSv4 errors into userland */

int nfs4_map_errors(int err)
@@ -224,6 +225,7 @@ struct nfs4_opendata { 
	struct path path;

	struct dentry *dir;

	struct nfs4_state_owner *owner;

	struct nfs4_state *state;

	struct iattr attrs;

	unsigned long timestamp;

	unsigned int rpc_done : 1;
@@ -296,6 +298,8 @@ static void nfs4_opendata_free(struct kref *kref) 
			struct nfs4_opendata, kref);



	nfs_free_seqid(p->o_arg.seqid);

	if (p->state != NULL)

		nfs4_put_open_state(p->state);

	nfs4_put_state_owner(p->owner);

	dput(p->dir);

	dput(p->path.dentry);
@@ -320,6 +324,15 @@ static int nfs4_wait_for_completion_rpc_task(struct rpc_task *task) 
	return ret;

}



static int can_open_delegated(struct nfs_delegation *delegation, mode_t open_flags)

{

	if ((delegation->type & open_flags) != open_flags)

		return 0;

	if (delegation->flags & NFS_DELEGATION_NEED_RECLAIM)

		return 0;

	return 1;

}



static void update_open_stateflags(struct nfs4_state *state, mode_t open_flags)

{

	switch (open_flags) {
@@ -380,6 +393,65 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_sta 
	spin_unlock(&state->owner->so_lock);

}



static void nfs4_return_incompatible_delegation(struct inode *inode, mode_t open_flags)

{

	struct nfs_delegation *delegation;



	rcu_read_lock();

	delegation = rcu_dereference(NFS_I(inode)->delegation);

	if (delegation == NULL || (delegation->type & open_flags) == open_flags) {

		rcu_read_unlock();

		return;

	}

	rcu_read_unlock();

	nfs_inode_return_delegation(inode);

}



static struct nfs4_state *nfs4_try_open_delegated(struct nfs4_opendata *opendata)

{

	struct nfs4_state *state = opendata->state;

	struct nfs_inode *nfsi = NFS_I(state->inode);

	struct nfs_delegation *delegation;

	int open_mode = opendata->o_arg.open_flags & (FMODE_READ|FMODE_WRITE|O_EXCL);

	nfs4_stateid stateid;

	int ret = -EAGAIN;



	rcu_read_lock();

	delegation = rcu_dereference(nfsi->delegation);

	if (delegation == NULL)

		goto out_unlock;

	for (;;) {

		if (!can_open_delegated(delegation, open_mode))

			break;

		/* Save the delegation */

		memcpy(stateid.data, delegation->stateid.data, sizeof(stateid.data));

		rcu_read_unlock();

		lock_kernel();

		ret = _nfs4_do_access(state->inode, state->owner->so_cred, open_mode);

		unlock_kernel();

		if (ret != 0)

			goto out;

		ret = -EAGAIN;

		rcu_read_lock();

		delegation = rcu_dereference(nfsi->delegation);

		if (delegation == NULL)

			break;

		/* Is the delegation still valid? */

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

			continue;

		rcu_read_unlock();

		update_open_stateid(state, NULL, &stateid, open_mode);

		goto out_return_state;

	}

out_unlock:

	rcu_read_unlock();

out:

	return ERR_PTR(ret);

out_return_state:

	atomic_inc(&state->count);

	return state;

}



static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)

{

	struct inode *inode;
@@ -388,6 +460,11 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data 
	nfs4_stateid *deleg_stateid = NULL;

	int ret;



	if (!data->rpc_done) {

		state = nfs4_try_open_delegated(data);

		goto out;

	}



	ret = -EAGAIN;

	if (!(data->f_attr.valid & NFS_ATTR_FATTR))

		goto err;
@@ -423,6 +500,7 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data 
	update_open_stateid(state, &data->o_res.stateid, deleg_stateid, data->o_arg.open_flags);

	rcu_read_unlock();

	iput(inode);

out:

	return state;

err_put_inode:

	iput(inode);
@@ -690,6 +768,23 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata) 
	

	if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)

		return;

	/*

	 * Check if we still need to send an OPEN call, or if we can use

	 * a delegation instead.

	 */

	if (data->state != NULL) {

		struct nfs_delegation *delegation;



		rcu_read_lock();

		delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);

		if (delegation != NULL &&

		   (delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0) {

			rcu_read_unlock();

			task->tk_action = NULL;

			return;

		}

		rcu_read_unlock();

	}

	/* Update sequence id. */

	data->o_arg.id = sp->so_owner_id.id;

	data->o_arg.clientid = sp->so_client->cl_clientid;
@@ -906,90 +1001,6 @@ static int nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *sta 
	return ret;

}



/*

 * Returns a referenced nfs4_state if there is an open delegation on the file

 */

static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred, struct nfs4_state **res)

{

	struct nfs_delegation *delegation;

	struct nfs_server *server = NFS_SERVER(inode);

	struct nfs_client *clp = server->nfs_client;

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs4_state_owner *sp = NULL;

	struct nfs4_state *state = NULL;

	int open_flags = flags & (FMODE_READ|FMODE_WRITE);

	int err;



	err = -ENOMEM;

	if (!(sp = nfs4_get_state_owner(server, cred))) {

		dprintk("%s: nfs4_get_state_owner failed!\n", __FUNCTION__);

		return err;

	}

	err = nfs4_recover_expired_lease(server);

	if (err != 0)

		goto out_put_state_owner;

	/* Protect against reboot recovery - NOTE ORDER! */

	down_read(&clp->cl_sem);

	/* Protect against delegation recall */

	down_read(&nfsi->rwsem);

	delegation = NFS_I(inode)->delegation;

	err = -ENOENT;

	if (delegation == NULL || (delegation->type & open_flags) != open_flags)

		goto out_err;

	err = -ENOMEM;

	state = nfs4_get_open_state(inode, sp);

	if (state == NULL)

		goto out_err;



	err = -ENOENT;

	if ((state->state & open_flags) == open_flags) {

		spin_lock(&inode->i_lock);

		update_open_stateflags(state, open_flags);

		spin_unlock(&inode->i_lock);

		goto out_ok;

	} else if (state->state != 0)

		goto out_put_open_state;



	lock_kernel();

	err = _nfs4_do_access(inode, cred, open_flags);

	unlock_kernel();

	if (err != 0)

		goto out_put_open_state;

	update_open_stateid(state, NULL, &delegation->stateid, open_flags);

out_ok:

	nfs4_put_state_owner(sp);

	up_read(&nfsi->rwsem);

	up_read(&clp->cl_sem);

	*res = state;

	return 0;

out_put_open_state:

	nfs4_put_open_state(state);

out_err:

	up_read(&nfsi->rwsem);

	up_read(&clp->cl_sem);

	if (err != -EACCES)

		nfs_inode_return_delegation(inode);

out_put_state_owner:

	nfs4_put_state_owner(sp);

	return err;

}



static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred)

{

	struct nfs4_exception exception = { };

	struct nfs4_state *res = ERR_PTR(-EIO);

	int err;



	do {

		err = _nfs4_open_delegated(inode, flags, cred, &res);

		if (err == 0)

			break;

		res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(inode),

					err, &exception));

	} while (exception.retry);

	return res;

}



/*

 * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*

 * fields corresponding to attributes that were used to store the verifier.
@@ -1027,12 +1038,17 @@ static int _nfs4_do_open(struct inode *dir, struct path *path, int flags, struct 
	status = nfs4_recover_expired_lease(server);

	if (status != 0)

		goto err_put_state_owner;

	if (path->dentry->d_inode != NULL)

		nfs4_return_incompatible_delegation(path->dentry->d_inode, flags & (FMODE_READ|FMODE_WRITE));

	down_read(&clp->cl_sem);

	status = -ENOMEM;

	opendata = nfs4_opendata_alloc(path, sp, flags, sattr);

	if (opendata == NULL)

		goto err_release_rwsem;



	if (path->dentry->d_inode != NULL)

		opendata->state = nfs4_get_open_state(path->dentry->d_inode, sp);



	status = _nfs4_proc_open(opendata);

	if (status != 0)

		goto err_opendata_put;
@@ -1099,6 +1115,11 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir, struct path *path, int 
			exception.retry = 1;

			continue;

		}

		if (status == -EAGAIN) {

			/* We must have found a delegation */

			exception.retry = 1;

			continue;

		}

		res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),

					status, &exception));

	} while (exception.retry);
@@ -1390,8 +1411,6 @@ nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, st 
	cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);

	if (IS_ERR(cred))

		return PTR_ERR(cred);

	state = nfs4_open_delegated(dentry->d_inode, openflags, cred);

	if (IS_ERR(state))

	state = nfs4_do_open(dir, &path, openflags, NULL, cred);

	put_rpccred(cred);

	if (IS_ERR(state)) {