pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process()

stable inclusion
from linux-4.19.173
commit 8a9ccffb3c1a6ecbfa2c811fe329f8220696dbc0

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

[ Upstream commit 814b8497 ]

If the server returns a new stateid that does not match the one in our
cache, then pnfs_layout_process() will leak the layout segments returned
by pnfs_mark_layout_stateid_invalid().

Fixes: 9888d837 ("pNFS: Force a retry of LAYOUTGET if the stateid doesn't match our cache")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/nfs/pnfs.c

@@ -2320,6 +2320,7 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
 	spin_unlock(&ino->i_lock);
 	lseg->pls_layout = lo;
 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
+	pnfs_free_lseg_list(&free_me);
 	return ERR_PTR(-EAGAIN);
 }