NFSv4: Don't hold the layoutget locks across multiple RPC calls

stable inclusion
from stable-4.19.247
commit 6b3fc1496e7227cd6a39a80bbfb7588ef7c7a010
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5FNPY


CVE: NA

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

[ Upstream commit 6949493884fe88500de4af182588e071cf1544ee ]

When doing layoutget as part of the open() compound, we have to be
careful to release the layout locks before we can call any further RPC
calls, such as setattr(). The reason is that those calls could trigger
a recall, which could deadlock.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>

fs/nfs/nfs4proc.c

@@ -2964,6 +2964,10 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
 	}
 
 out:
+	if (opendata->lgp) {
+		nfs4_lgopen_release(opendata->lgp);
+		opendata->lgp = NULL;
+	}
 	if (!opendata->cancelled)
 		nfs4_sequence_free_slot(&opendata->o_res.seq_res);
 	return ret;