md: don't clear MD_CHANGE_CLEAN in md_update_sb() for external arrays
If this bit is cleared in md_update_sb() the kernel will allow writes to the
array if userspace triggers md_allow_write(), e.g. through stripe_cache_size,
when mdmon is not active. When mdmon is active the array transitions to
active-idle bypassing write-pending, setting up a race for mdmon to set the
array clean before a write arrives.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c148b63..a1f6b59 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2167,9 +2167,10 @@
rdev->recovery_offset = mddev->curr_resync_completed;
}
- if (mddev->external || !mddev->persistent) {
+ if (!mddev->persistent) {
+ if (!mddev->external)
+ clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
clear_bit(MD_CHANGE_DEVS, &mddev->flags);
- clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
wake_up(&mddev->sb_wait);
return;
}