[PATCH v2] md/bitmap: fix missing_pages restore in resize rollback

[Chengyu Liu <lui2012qwq@gmail.com>]

The rollback for a failed clustered-raid bitmap preallocation copies
old_counts.pages into missing_pages instead of old_counts.missing_pages.
The counter then reports every page as missing and can grow past the
page count as pages are freed later, making the used_pages stat in
/proc/mdstat wrap around.  Accounting only, no corruption.

Fixes: c9d650322829 ("md-cluster: always setup in-memory bitmap")
Signed-off-by: Chengyu Liu <lui2012qwq@gmail.com>
---
v2: add Fixes tag (spotted by sashiko)
v1: https://lore.kernel.org/linux-raid/20261107164305.11476-1-lui2012qwq@gmail.com/

 drivers/md/md-bitmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index b8325cb09a37..66ed92a0715b 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2495,7 +2495,7 @@
 				/* restore some fields from old_counts */
 				bitmap->counts.bp = old_counts.bp;
 				bitmap->counts.pages = old_counts.pages;
-				bitmap->counts.missing_pages = old_counts.pages;
+				bitmap->counts.missing_pages = old_counts.missing_pages;
 				bitmap->counts.chunkshift = old_counts.chunkshift;
 				bitmap->counts.chunks = old_counts.chunks;
 				bitmap->mddev->bitmap_info.chunksize =
-- 
2.25.1