[PATCH 4.17 065/336] pnfs: Dont release the sequence slot until weve processed layoutget on open

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

[ Upstream commit ae55e59da0e401893b3c52b575fc18a00623d0a1 ]

If the server recalls the layout that was just handed out, we risk hitting
a race as described in RFC5661 Section 2.10.6.3 unless we ensure that we
release the sequence slot after processing the LAYOUTGET operation that
was sent as part of the OPEN compound.

Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/nfs/nfs4proc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2807,7 +2807,7 @@ static int _nfs4_open_and_get_state(stru
 	if (ret != 0)
 		goto out;
 
-	state = nfs4_opendata_to_nfs4_state(opendata);
+	state = _nfs4_opendata_to_nfs4_state(opendata);
 	ret = PTR_ERR(state);
 	if (IS_ERR(state))
 		goto out;
@@ -2843,6 +2843,7 @@ static int _nfs4_open_and_get_state(stru
 			nfs4_schedule_stateid_recovery(server, state);
 	}
 out:
+	nfs4_sequence_free_slot(&opendata->o_res.seq_res);
 	return ret;
 }