Commit 2dbf8dff authored by Trond Myklebust's avatar Trond Myklebust
Browse files

pNFS: Always free the session slot on error in nfs4_layoutget_handle_exception 



Right now, we can call nfs_commit_inode() while holding the session slot,
which could lead to NFSv4 deadlocks. Ensure we only keep the slot if
the server returned a layout that we have to process.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent d5681f59

fs/nfs/nfs4proc.c

+10 −7
Original line number Diff line number Diff line
@@ -8650,6 +8650,8 @@ nfs4_layoutget_handle_exception(struct rpc_task *task, 


	dprintk("--> %s tk_status => %d\n", __func__, -task->tk_status);



	nfs4_sequence_free_slot(&lgp->res.seq_res);



	switch (nfs4err) {

	case 0:

		goto out;
@@ -8714,7 +8716,6 @@ nfs4_layoutget_handle_exception(struct rpc_task *task, 
		goto out;

	}



	nfs4_sequence_free_slot(&lgp->res.seq_res);

	err = nfs4_handle_exception(server, nfs4err, exception);

	if (!status) {

		if (exception->retry)
@@ -8786,20 +8787,22 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout) 
	if (IS_ERR(task))

		return ERR_CAST(task);

	status = rpc_wait_for_completion_task(task);

	if (status == 0) {

	if (status != 0)

		goto out;



	/* if layoutp->len is 0, nfs4_layoutget_prepare called rpc_exit */

	if (task->tk_status < 0 || lgp->res.layoutp->len == 0) {

		status = nfs4_layoutget_handle_exception(task, lgp, &exception);

		*timeout = exception.timeout;

	}



	} else

		lseg = pnfs_layout_process(lgp);

out:

	trace_nfs4_layoutget(lgp->args.ctx,

			&lgp->args.range,

			&lgp->res.range,

			&lgp->res.stateid,

			status);



	/* if layoutp->len is 0, nfs4_layoutget_prepare called rpc_exit */

	if (status == 0 && lgp->res.layoutp->len)

		lseg = pnfs_layout_process(lgp);

	rpc_put_task(task);

	dprintk("<-- %s status=%d\n", __func__, status);

	if (status)