[PATCH 5.4 345/411] NFSv4: Dont hold the layoutget locks across multiple RPC calls

Greg Kroah-Hartman
2022-06-13T11:42:04Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ 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>
---
fs/nfs/nfs4proc.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cf3b00751ff6..ba4a03a69fbf 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3041,6 +3041,10 @@ 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;
--
2.35.1