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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: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
hifive-unleashed-5.1
NeilBrown 2016-06-02 16:19:52 +10:00 committed by Shaohua Li
parent e50d399232
commit 3f232d6a95
1 changed files with 4 additions and 3 deletions
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7
drivers/md/raid5.c
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@ -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;
}