diff options
Diffstat (limited to 'drivers/md/raid5.c')
| -rw-r--r-- | drivers/md/raid5.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index bb4b12e370df..3bbc6d647044 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3766,7 +3766,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped int new_data_disks = conf->raid_disks - conf->max_degraded; int i; int dd_idx; - sector_t writepos, safepos, gap; + sector_t writepos, readpos, safepos; sector_t stripe_addr; int reshape_sectors; struct list_head stripes; @@ -3806,26 +3806,46 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped */ writepos = conf->reshape_progress; sector_div(writepos, new_data_disks); + readpos = conf->reshape_progress; + sector_div(readpos, data_disks); safepos = conf->reshape_safe; sector_div(safepos, data_disks); if (mddev->delta_disks < 0) { writepos -= reshape_sectors; + readpos += reshape_sectors; safepos += reshape_sectors; - gap = conf->reshape_safe - conf->reshape_progress; } else { writepos += reshape_sectors; + readpos -= reshape_sectors; safepos -= reshape_sectors; - gap = conf->reshape_progress - conf->reshape_safe; } + /* 'writepos' is the most advanced device address we might write. + * 'readpos' is the least advanced device address we might read. + * 'safepos' is the least address recorded in the metadata as having + * been reshaped. + * If 'readpos' is behind 'writepos', then there is no way that we can + * ensure safety in the face of a crash - that must be done by userspace + * making a backup of the data. So in that case there is no particular + * rush to update metadata. + * Otherwise if 'safepos' is behind 'writepos', then we really need to + * update the metadata to advance 'safepos' to match 'readpos' so that + * we can be safe in the event of a crash. + * So we insist on updating metadata if safepos is behind writepos and + * readpos is beyond writepos. + * In any case, update the metadata every 10 seconds. + * Maybe that number should be configurable, but I'm not sure it is + * worth it.... maybe it could be a multiple of safemode_delay??? + */ if ((mddev->delta_disks < 0 - ? writepos < safepos - : writepos > safepos) || - gap > (new_data_disks)*3000*2 /*3Meg*/) { + ? (safepos > writepos && readpos < writepos) + : (safepos < writepos && readpos > writepos)) || + time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, atomic_read(&conf->reshape_stripes)==0); mddev->reshape_position = conf->reshape_progress; + conf->reshape_checkpoint = jiffies; set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, mddev->flags == 0 || @@ -3923,6 +3943,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped wait_event(conf->wait_for_overlap, atomic_read(&conf->reshape_stripes) == 0); mddev->reshape_position = conf->reshape_progress; + conf->reshape_checkpoint = jiffies; set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, @@ -4957,6 +4978,7 @@ static int raid5_start_reshape(mddev_t *mddev) spin_unlock_irq(&conf->device_lock); return -EAGAIN; } + conf->reshape_checkpoint = jiffies; md_wakeup_thread(mddev->sync_thread); md_new_event(mddev); return 0; |