[PATCH 3.11 176/208] dm thin: re-establish read-only state when switching to fail mode

[Luis Henriques]

3.11.10.2 -stable review patch.  If anyone has any objections, please let me know.

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

From: Joe Thornber <ejt at redhat.com>

commit 5383ef3a929a1366e2ced45cd6d74be7aa2a2281 upstream.

If the thin-pool transitioned to fail mode and the thin-pool's table
were reloaded for some reason: the new table's default pool mode would
be read-write, though it will transition to fail mode during resume.

When the pool mode transitions directly from PM_WRITE to PM_FAIL we need
to re-establish the intermediate read-only state in both the metadata
and persistent-data block manager (as is usually done with the normal
pool mode transition sequence: PM_WRITE -> PM_READ_ONLY -> PM_FAIL).

Signed-off-by: Joe Thornber <ejt at redhat.com>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/dm-thin.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index e36f81e..930a7e3 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1389,6 +1389,7 @@ static void set_pool_mode(struct pool *pool, enum pool_mode mode)
 	switch (mode) {
 	case PM_FAIL:
 		DMERR("switching pool to failure mode");
+		dm_pool_metadata_read_only(pool->pmd);
 		pool->process_bio = process_bio_fail;
 		pool->process_discard = process_bio_fail;
 		pool->process_prepared_mapping = process_prepared_mapping_fail;
-- 
1.8.3.2