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md/raid5: change reshape-progress measurement to cope with reshaping backwards.
When reducing the number of devices in a raid4/5/6, the reshape process has to start at the end of the array and work down to the beginning. So we need to handle expand_progress and expand_lo differently. This patch renames "expand_progress" and "expand_lo" to avoid the implication that anything is getting bigger (expand->reshape) and every place they are used, we make sure that they are used the right way depending on whether delta_disks is positive or negative. Signed-off-by: NeilBrown <neilb@suse.de>
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NeilBrown
parent
cea9c22800
commit
fef9c61fdf
@ -3593,24 +3593,28 @@ static int make_request(struct request_queue *q, struct bio * bi)
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retry:
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previous = 0;
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prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
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if (likely(conf->expand_progress == MaxSector))
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if (likely(conf->reshape_progress == MaxSector))
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disks = conf->raid_disks;
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else {
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/* spinlock is needed as expand_progress may be
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/* spinlock is needed as reshape_progress may be
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* 64bit on a 32bit platform, and so it might be
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* possible to see a half-updated value
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* Ofcourse expand_progress could change after
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* Ofcourse reshape_progress could change after
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* the lock is dropped, so once we get a reference
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* to the stripe that we think it is, we will have
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* to check again.
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*/
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spin_lock_irq(&conf->device_lock);
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disks = conf->raid_disks;
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if (logical_sector >= conf->expand_progress) {
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if (mddev->delta_disks < 0
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? logical_sector < conf->reshape_progress
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: logical_sector >= conf->reshape_progress) {
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disks = conf->previous_raid_disks;
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previous = 1;
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} else {
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if (logical_sector >= conf->expand_lo) {
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if (mddev->delta_disks < 0
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? logical_sector < conf->reshape_safe
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: logical_sector >= conf->reshape_safe) {
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spin_unlock_irq(&conf->device_lock);
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schedule();
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goto retry;
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@ -3630,7 +3634,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
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sh = get_active_stripe(conf, new_sector, previous,
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(bi->bi_rw&RWA_MASK));
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if (sh) {
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if (unlikely(conf->expand_progress != MaxSector)) {
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if (unlikely(conf->reshape_progress != MaxSector)) {
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/* expansion might have moved on while waiting for a
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* stripe, so we must do the range check again.
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* Expansion could still move past after this
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@ -3641,8 +3645,10 @@ static int make_request(struct request_queue *q, struct bio * bi)
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*/
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int must_retry = 0;
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spin_lock_irq(&conf->device_lock);
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if (logical_sector < conf->expand_progress &&
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disks == conf->previous_raid_disks)
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if ((mddev->delta_disks < 0
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? logical_sector >= conf->reshape_progress
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: logical_sector < conf->reshape_progress)
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&& disks == conf->previous_raid_disks)
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/* mismatch, need to try again */
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must_retry = 1;
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spin_unlock_irq(&conf->device_lock);
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@ -3720,13 +3726,20 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
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int dd_idx;
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sector_t writepos, safepos, gap;
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if (sector_nr == 0 &&
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conf->expand_progress != 0) {
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/* restarting in the middle, skip the initial sectors */
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sector_nr = conf->expand_progress;
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if (sector_nr == 0) {
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/* If restarting in the middle, skip the initial sectors */
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if (mddev->delta_disks < 0 &&
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conf->reshape_progress < raid5_size(mddev, 0, 0)) {
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sector_nr = raid5_size(mddev, 0, 0)
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- conf->reshape_progress;
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} else if (mddev->delta_disks > 0 &&
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conf->reshape_progress > 0)
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sector_nr = conf->reshape_progress;
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sector_div(sector_nr, new_data_disks);
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*skipped = 1;
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return sector_nr;
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if (sector_nr) {
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*skipped = 1;
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return sector_nr;
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}
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}
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/* we update the metadata when there is more than 3Meg
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@ -3734,28 +3747,37 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
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* probably be time based) or when the data about to be
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* copied would over-write the source of the data at
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* the front of the range.
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* i.e. one new_stripe forward from expand_progress new_maps
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* to after where expand_lo old_maps to
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* i.e. one new_stripe along from reshape_progress new_maps
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* to after where reshape_safe old_maps to
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*/
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writepos = conf->expand_progress +
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conf->chunk_size/512*(new_data_disks);
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writepos = conf->reshape_progress;
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sector_div(writepos, new_data_disks);
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safepos = conf->expand_lo;
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safepos = conf->reshape_safe;
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sector_div(safepos, data_disks);
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gap = conf->expand_progress - conf->expand_lo;
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if (mddev->delta_disks < 0) {
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writepos -= conf->chunk_size/512;
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safepos += conf->chunk_size/512;
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gap = conf->reshape_safe - conf->reshape_progress;
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} else {
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writepos += conf->chunk_size/512;
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safepos -= conf->chunk_size/512;
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gap = conf->reshape_progress - conf->reshape_safe;
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}
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if (writepos >= safepos ||
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if ((mddev->delta_disks < 0
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? writepos < safepos
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: writepos > safepos) ||
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gap > (new_data_disks)*3000*2 /*3Meg*/) {
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/* Cannot proceed until we've updated the superblock... */
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wait_event(conf->wait_for_overlap,
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atomic_read(&conf->reshape_stripes)==0);
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mddev->reshape_position = conf->expand_progress;
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mddev->reshape_position = conf->reshape_progress;
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set_bit(MD_CHANGE_DEVS, &mddev->flags);
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md_wakeup_thread(mddev->thread);
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wait_event(mddev->sb_wait, mddev->flags == 0 ||
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kthread_should_stop());
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spin_lock_irq(&conf->device_lock);
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conf->expand_lo = mddev->reshape_position;
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conf->reshape_safe = mddev->reshape_position;
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spin_unlock_irq(&conf->device_lock);
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wake_up(&conf->wait_for_overlap);
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}
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@ -3792,7 +3814,10 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
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release_stripe(sh);
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}
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spin_lock_irq(&conf->device_lock);
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conf->expand_progress = (sector_nr + i) * new_data_disks;
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if (mddev->delta_disks < 0)
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conf->reshape_progress -= i * new_data_disks;
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else
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conf->reshape_progress += i * new_data_disks;
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spin_unlock_irq(&conf->device_lock);
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/* Ok, those stripe are ready. We can start scheduling
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* reads on the source stripes.
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@ -3823,14 +3848,14 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped
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/* Cannot proceed until we've updated the superblock... */
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wait_event(conf->wait_for_overlap,
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atomic_read(&conf->reshape_stripes) == 0);
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mddev->reshape_position = conf->expand_progress;
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mddev->reshape_position = conf->reshape_progress;
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set_bit(MD_CHANGE_DEVS, &mddev->flags);
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md_wakeup_thread(mddev->thread);
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wait_event(mddev->sb_wait,
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!test_bit(MD_CHANGE_DEVS, &mddev->flags)
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|| kthread_should_stop());
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spin_lock_irq(&conf->device_lock);
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conf->expand_lo = mddev->reshape_position;
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conf->reshape_safe = mddev->reshape_position;
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spin_unlock_irq(&conf->device_lock);
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wake_up(&conf->wait_for_overlap);
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}
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@ -4283,7 +4308,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
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conf->max_degraded = 1;
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conf->algorithm = mddev->new_layout;
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conf->max_nr_stripes = NR_STRIPES;
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conf->expand_progress = mddev->reshape_position;
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conf->reshape_progress = mddev->reshape_position;
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memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
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conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
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@ -4441,9 +4466,9 @@ static int run(mddev_t *mddev)
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print_raid5_conf(conf);
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if (conf->expand_progress != MaxSector) {
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if (conf->reshape_progress != MaxSector) {
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printk("...ok start reshape thread\n");
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conf->expand_lo = conf->expand_progress;
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conf->reshape_safe = conf->reshape_progress;
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atomic_set(&conf->reshape_stripes, 0);
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clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
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clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
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@ -4782,8 +4807,11 @@ static int raid5_start_reshape(mddev_t *mddev)
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spin_lock_irq(&conf->device_lock);
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conf->previous_raid_disks = conf->raid_disks;
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conf->raid_disks += mddev->delta_disks;
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conf->expand_progress = 0;
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conf->expand_lo = 0;
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if (mddev->delta_disks < 0)
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conf->reshape_progress = raid5_size(mddev, 0, 0);
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else
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conf->reshape_progress = 0;
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conf->reshape_safe = conf->reshape_progress;
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spin_unlock_irq(&conf->device_lock);
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/* Add some new drives, as many as will fit.
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@ -4825,7 +4853,7 @@ static int raid5_start_reshape(mddev_t *mddev)
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mddev->recovery = 0;
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spin_lock_irq(&conf->device_lock);
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mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
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conf->expand_progress = MaxSector;
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conf->reshape_progress = MaxSector;
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spin_unlock_irq(&conf->device_lock);
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return -EAGAIN;
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}
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@ -4842,7 +4870,7 @@ static void end_reshape(raid5_conf_t *conf)
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spin_lock_irq(&conf->device_lock);
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conf->previous_raid_disks = conf->raid_disks;
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conf->expand_progress = MaxSector;
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conf->reshape_progress = MaxSector;
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spin_unlock_irq(&conf->device_lock);
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/* read-ahead size must cover two whole stripes, which is
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@ -337,11 +337,16 @@ struct raid5_private_data {
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int raid_disks;
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int max_nr_stripes;
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/* used during an expand */
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sector_t expand_progress; /* MaxSector when no expand happening */
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sector_t expand_lo; /* from here up to expand_progress it out-of-bounds
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* as we haven't flushed the metadata yet
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*/
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/* reshape_progress is the leading edge of a 'reshape'
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* It has value MaxSector when no reshape is happening
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* If delta_disks < 0, it is the last sector we started work on,
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* else is it the next sector to work on.
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*/
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sector_t reshape_progress;
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/* reshape_safe is the trailing edge of a reshape. We know that
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* before (or after) this address, all reshape has completed.
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*/
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sector_t reshape_safe;
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int previous_raid_disks;
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struct list_head handle_list; /* stripes needing handling */
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