Commit c8da19b9 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1: Fix an ABBA locking issue with session and state serialisation 



Ensure that if nfs_wait_on_sequence() causes our rpc task to wait for
an NFSv4 state serialisation lock, then we also drop the session slot.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
parent c21443c2

fs/nfs/nfs4proc.c

+20 −12
Original line number Diff line number Diff line
@@ -1466,7 +1466,7 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata) 
	struct nfs4_state_owner *sp = data->owner;



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

		return;

		goto out_wait;

	/*

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

	 * a delegation instead.
@@ -1501,6 +1501,7 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata) 
	rcu_read_unlock();

out_no_action:

	task->tk_action = NULL;

out_wait:

	nfs4_sequence_done(task, &data->o_res.seq_res);

}
@@ -2179,7 +2180,7 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data) 


	dprintk("%s: begin!\n", __func__);

	if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)

		return;

		goto out_wait;



	task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];

	calldata->arg.fmode = FMODE_READ|FMODE_WRITE;
@@ -2201,16 +2202,14 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data) 


	if (!call_close) {

		/* Note: exit _without_ calling nfs4_close_done */

		task->tk_action = NULL;

		nfs4_sequence_done(task, &calldata->res.seq_res);

		goto out;

		goto out_no_action;

	}



	if (calldata->arg.fmode == 0) {

		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];

		if (calldata->roc &&

		    pnfs_roc_drain(inode, &calldata->roc_barrier, task))

			goto out;

			goto out_wait;

	}



	nfs_fattr_init(calldata->res.fattr);
@@ -2220,8 +2219,12 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data) 
				&calldata->res.seq_res,

				task) != 0)

		nfs_release_seqid(calldata->arg.seqid);

out:

	dprintk("%s: done!\n", __func__);

	return;

out_no_action:

	task->tk_action = NULL;

out_wait:

	nfs4_sequence_done(task, &calldata->res.seq_res);

}



static const struct rpc_call_ops nfs4_close_ops = {
@@ -4452,12 +4455,10 @@ static void nfs4_locku_prepare(struct rpc_task *task, void *data) 
	struct nfs4_unlockdata *calldata = data;



	if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)

		return;

		goto out_wait;

	if (test_bit(NFS_LOCK_INITIALIZED, &calldata->lsp->ls_flags) == 0) {

		/* Note: exit _without_ running nfs4_locku_done */

		task->tk_action = NULL;

		nfs4_sequence_done(task, &calldata->res.seq_res);

		return;

		goto out_no_action;

	}

	calldata->timestamp = jiffies;

	if (nfs4_setup_sequence(calldata->server,
@@ -4465,6 +4466,11 @@ static void nfs4_locku_prepare(struct rpc_task *task, void *data) 
				&calldata->res.seq_res,

				task) != 0)

		nfs_release_seqid(calldata->arg.seqid);

	return;

out_no_action:

	task->tk_action = NULL;

out_wait:

	nfs4_sequence_done(task, &calldata->res.seq_res);

}



static const struct rpc_call_ops nfs4_locku_ops = {
@@ -4612,7 +4618,7 @@ static void nfs4_lock_prepare(struct rpc_task *task, void *calldata) 


	dprintk("%s: begin!\n", __func__);

	if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)

		return;

		goto out_wait;

	/* Do we need to do an open_to_lock_owner? */

	if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED)) {

		if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0) {
@@ -4632,6 +4638,8 @@ static void nfs4_lock_prepare(struct rpc_task *task, void *calldata) 
	nfs_release_seqid(data->arg.open_seqid);

out_release_lock_seqid:

	nfs_release_seqid(data->arg.lock_seqid);

out_wait:

	nfs4_sequence_done(task, &data->res.seq_res);

	dprintk("%s: done!, ret = %d\n", __func__, data->rpc_status);

}