From c1a6e218334ac561a695fa4cefd69208ba93107e Mon Sep 17 00:00:00 2001
From: Zdenek Kabelac <zkabelac@redhat.com>
Date: Sat, 14 Sep 2019 01:08:14 +0200
Subject: [PATCH 6/6] thin: activate layer pool aas read-only LV

When lvm2 is activating layered pool LV (to basically keep pool opened,
the other function used to be 'locking' be in sync with DM table)
use this LV in read-only mode - this prevents 'write' access into
data volume content of thin-pool.

Note: since EMPTY/unused thin-pool is created as 'public LV' for generic
use by any user who i.e. wish to maintain thin-pool and thins himself.
At this moment, thin-pool appears as writable LV.  As soon as the 1st.
thinLV is created, layer volume will appear is 'read-only' LV from this moment.

(cherry picked from commit 2e51535b18f3a05428f087f3916ebce5c08d58d1)

Conflicts:
	WHATS_NEW
---
 WHATS_NEW                  | 1 +
 lib/activate/dev_manager.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/WHATS_NEW b/WHATS_NEW
index d1f4530..00b84f9 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -2,6 +2,7 @@ Version 2.02.187 -
 ===================================
   Prevent creating VGs with PVs with different logical block sizes.
   Pvmove runs in exlusively activating mode for exclusively active LVs.
+  Activate thin-pool layered volume as 'read-only' device.
   Enhance validation for thin and cache pool conversion and swapping.
 
 Version 2.02.186 - 27th August 2019
diff --git a/lib/activate/dev_manager.c b/lib/activate/dev_manager.c
index dc64159..56608e3 100644
--- a/lib/activate/dev_manager.c
+++ b/lib/activate/dev_manager.c
@@ -84,6 +84,11 @@ int read_only_lv(const struct logical_volume *lv, const struct lv_activate_opts
 	if (lv_is_raid_image(lv) || lv_is_raid_metadata(lv))
 		return 0; /* Keep RAID SubLvs writable */
 
+	if (!layer) {
+		if (lv_is_thin_pool(lv))
+			return 1;
+	}
+
 	return (laopts->read_only || !(lv->status & LVM_WRITE));
 }
 
-- 
1.8.3.1