thin: fix upgrade regression

Older lvm2 tools where always providing linear mapping for thin pool.
Recent lvm2 version however support external usage of thin pool and
empty/unused pools are loaded without such external linear mapping.

So this patch covers 'upgrade' problem, where older tool has activated
thin-pool with 'linear' layer mapping, and newer tools didn't expected
such mapping to exist and were not able to deactivate such table.

So before checking for new layout in dm-table, check if there is not
an old one already there.

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/activate/activate.c b/lib/activate/activate.c
index dbfb42705..c0545317e 100644
--- a/lib/activate/activate.c
+++ b/lib/activate/activate.c
@@ -655,8 +655,13 @@ static int _lv_info(struct cmd_context *cmd, const struct logical_volume *lv,
 	}
 
 	/* New thin-pool has no layer, but -tpool suffix needs to be queried */
-	if (!use_layer && lv_is_new_thin_pool(lv))
-		use_layer = 1;
+	if (!use_layer && lv_is_new_thin_pool(lv)) {
+		/* Check if there isn't existing old thin pool mapping in the table */
+		if (!dev_manager_info(cmd->mem, lv, NULL, 0, 0, &dminfo, NULL, NULL))
+			return_0;
+		if (!dminfo.exists)
+			use_layer = 1;
+	}
 
 	if (seg_status)
 		seg_status->seg = seg;