[PATCH 4.17 026/336] nfsd: fix error handling in nfs4_set_delegation()

[Greg Kroah-Hartman]

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

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

From: Andrew Elble <aweits@xxxxxxx>

[ Upstream commit 692ad280bff3e81721ab138b9455948ab5289acf ]

I noticed a memory corruption crash in nfsd in
4.17-rc1. This patch corrects the issue.

Fix to return error if the delegation couldn't be hashed or there was
a recall in progress. Use the existing error path instead of
destroy_delegation() for readability.

Signed-off-by: Andrew Elble <aweits@xxxxxxx>
Fixes: 353601e7d323c ("nfsd: create a separate lease for each delegation")
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/nfsd/nfs4state.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4378,8 +4378,11 @@ nfs4_set_delegation(struct nfs4_client *
 	spin_unlock(&state_lock);
 
 	if (status)
-		destroy_unhashed_deleg(dp);
+		goto out_unlock;
+
 	return dp;
+out_unlock:
+	vfs_setlease(fp->fi_deleg_file, F_UNLCK, NULL, (void **)&dp);
 out_clnt_odstate:
 	put_clnt_odstate(dp->dl_clnt_odstate);
 out_stid: