From aa03a91ffaefcffb397cddf88b97215b3eff726d Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Fri, 21 Jul 2017 13:16:06 -0400
Subject: [PATCH] dm integrity: WARN_ON if variables representing journal usage
 get out of sync
Git-commit: aa03a91ffaefcffb397cddf88b97215b3eff726d
Patch-mainline: v4.13-rc3
References: fate#322738,fate#322919,fate#322950,fate#323773

If this WARN_ON triggers it speaks to programmer error, and likely
implies corruption, but no released kernel should trigger it.  This
WARN_ON serves to assist DM integrity developers as changes are
made/tested in the future.

BUG_ON is excessive for catching programmer error, if a user or
developer would like warnings to trigger a panic, they can enable that
via /proc/sys/kernel/panic_on_warn

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/dm-integrity.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index be3b6f42095c..a7a3708700c0 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1729,6 +1729,8 @@ static void pad_uncommitted(struct dm_integrity_c *ic)
 		wraparound_section(ic, &ic->free_section);
 		ic->n_uncommitted_sections++;
 	}
+	WARN_ON(ic->journal_sections * ic->journal_section_entries !=
+		(ic->n_uncommitted_sections + ic->n_committed_sections) * ic->journal_section_entries + ic->free_sectors);
 }
 
 static void integrity_commit(struct work_struct *w)
-- 
2.13.1