[PATCH] nfsd: call cache_put if xdr_reserve_space returns NULL

[Guoqing Jiang <guoqing.jiang@linux.dev>]

If no enough buffer space available, but idmap_lookup have triggered
lookup_fn which calls cache_get and returns successfully. Then we
missed to call cache_put here which pairs with cache_get.

Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
---
 fs/nfsd/nfs4idmap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 7a806ac13e31..7abddf7d8f6d 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -594,8 +594,10 @@ static __be32 idmap_id_to_name(struct xdr_stream *xdr,
 	ret = strlen(item->name);
 	WARN_ON_ONCE(ret > IDMAP_NAMESZ);
 	p = xdr_reserve_space(xdr, ret + 4);
-	if (!p)
+	if (!p) {
+		cache_put(&item->h, nn->idtoname_cache);
 		return nfserr_resource;
+	}
 	p = xdr_encode_opaque(p, item->name, ret);
 	cache_put(&item->h, nn->idtoname_cache);
 	return 0;
-- 
2.35.3