md: set MD_CHANGE_PENDING in a atomic region
Some code waits for a metadata update by:
1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
2. setting MD_CHANGE_PENDING and waking the management thread
3. waiting for MD_CHANGE_PENDING to be cleared
If the first two are done without locking, the code in md_update_sb()
which checks if it needs to repeat might test if an update is needed
before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
in the wait returning early.
So make sure all places that set MD_CHANGE_PENDING are atomicial, and
bit_clear_unless (suggested by Neil) is introduced for the purpose.
Cc: Martin Kepplinger <martink@posteo.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: <linux-kernel@vger.kernel.org>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 84e24e6..c7de2a5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1102,8 +1102,8 @@
bio->bi_iter.bi_sector < conf->reshape_progress))) {
/* Need to update reshape_position in metadata */
mddev->reshape_position = conf->reshape_progress;
- set_bit(MD_CHANGE_DEVS, &mddev->flags);
- set_bit(MD_CHANGE_PENDING, &mddev->flags);
+ set_mask_bits(&mddev->flags, 0,
+ BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
md_wakeup_thread(mddev->thread);
wait_event(mddev->sb_wait,
!test_bit(MD_CHANGE_PENDING, &mddev->flags));
@@ -1591,8 +1591,8 @@
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
set_bit(Blocked, &rdev->flags);
set_bit(Faulty, &rdev->flags);
- set_bit(MD_CHANGE_DEVS, &mddev->flags);
- set_bit(MD_CHANGE_PENDING, &mddev->flags);
+ set_mask_bits(&mddev->flags, 0,
+ BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
spin_unlock_irqrestore(&conf->device_lock, flags);
printk(KERN_ALERT
"md/raid10:%s: Disk failure on %s, disabling device.\n"