ext4: fix potential htree corruption when growing large_dir directories

Commit b5776e75 ("ext4: fix potential htree index checksum
corruption) removed a required restart when multiple levels of index
nodes need to be split.  Fix this to avoid directory htree corruptions
when using the large_dir feature.

Cc: stable@kernel.org # v5.11
Cc: Благодаренко Артём <artem.blagodarenko@gmail.com>
Fixes: b5776e75 ("ext4: fix potential htree index checksum corruption)
Reported-by: NDenis <denis@voxelsoft.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

fs/ext4/namei.c

@@ -2517,7 +2517,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
 				goto journal_error;
 			err = ext4_handle_dirty_dx_node(handle, dir,
 							frame->bh);
-			if (err)
+			if (restart || err)
 				goto journal_error;
 		} else {
 			struct dx_root *dxroot;