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Commit 3f232d6a authored by NeilBrown's avatar NeilBrown Committed by Shaohua Li
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md/raid5: add rcu protection to rdev accesses in want_replace 



Being in the middle of resync is no longer protection against failed
rdevs disappearing.  So add rcu protection.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent e50d3992

drivers/md/raid5.c

+4 −3
Original line number Diff line number Diff line
@@ -3239,15 +3239,16 @@ static int want_replace(struct stripe_head *sh, int disk_idx) 
{

	struct md_rdev *rdev;

	int rv = 0;

	/* Doing recovery so rcu locking not required */

	rdev = sh->raid_conf->disks[disk_idx].replacement;



	rcu_read_lock();

	rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);

	if (rdev

	    && !test_bit(Faulty, &rdev->flags)

	    && !test_bit(In_sync, &rdev->flags)

	    && (rdev->recovery_offset <= sh->sector

		|| rdev->mddev->recovery_cp <= sh->sector))

		rv = 1;



	rcu_read_unlock();

	return rv;

}