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

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: 9888d837f3 ("pNFS: Force a retry of LAYOUTGET if the stateid doesn't match our cache")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/pnfs.c

@@ -2417,6 +2417,7 @@ out_forget:
 	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);
 }