Messages in this thread | | | Date | Thu, 16 Mar 2006 22:01:37 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 006 of 13] md: Infrastructure to allow normal IO to continue while array is expanding. |
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NeilBrown <neilb@suse.de> wrote: > > - retry: > prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); > - sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK)); > + sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK)); > if (sh) { > - if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { > - /* Add failed due to overlap. Flush everything > + if (unlikely(conf->expand_progress != MaxSector)) { > + /* expansion might have moved on while waiting for a > + * stripe, so we much do the range check again. > + */ > + int must_retry = 0; > + spin_lock_irq(&conf->device_lock); > + if (logical_sector < conf->expand_progress && > + disks == conf->previous_raid_disks) > + /* mismatch, need to try again */ > + must_retry = 1; > + spin_unlock_irq(&conf->device_lock); > + if (must_retry) { > + release_stripe(sh); > + goto retry; > + } > + }
The locking in here looks strange. We take the lock, do some arithmetic and some tests and then drop the lock again. Is it not possible that the result of those tests now becomes invalid?
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