Commit b578d55f authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[PATCH] md: Only checkpoint expansion progress occasionally

Instead of checkpointing at each stripe, only checkpoint when a new write
would overwrite uncheckpointed data.  Block any write to the uncheckpointed
area.  Arbitrarily checkpoint at least every 3Meg.
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f6705578
...@@ -1762,8 +1762,9 @@ static int make_request(request_queue_t *q, struct bio * bi) ...@@ -1762,8 +1762,9 @@ static int make_request(request_queue_t *q, struct bio * bi)
for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
DEFINE_WAIT(w); DEFINE_WAIT(w);
int disks; int disks;
retry: retry:
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
if (likely(conf->expand_progress == MaxSector)) if (likely(conf->expand_progress == MaxSector))
disks = conf->raid_disks; disks = conf->raid_disks;
else { else {
...@@ -1771,6 +1772,13 @@ static int make_request(request_queue_t *q, struct bio * bi) ...@@ -1771,6 +1772,13 @@ static int make_request(request_queue_t *q, struct bio * bi)
disks = conf->raid_disks; disks = conf->raid_disks;
if (logical_sector >= conf->expand_progress) if (logical_sector >= conf->expand_progress)
disks = conf->previous_raid_disks; disks = conf->previous_raid_disks;
else {
if (logical_sector >= conf->expand_lo) {
spin_unlock_irq(&conf->device_lock);
schedule();
goto retry;
}
}
spin_unlock_irq(&conf->device_lock); spin_unlock_irq(&conf->device_lock);
} }
new_sector = raid5_compute_sector(logical_sector, disks, disks - 1, new_sector = raid5_compute_sector(logical_sector, disks, disks - 1,
...@@ -1779,7 +1787,6 @@ static int make_request(request_queue_t *q, struct bio * bi) ...@@ -1779,7 +1787,6 @@ static int make_request(request_queue_t *q, struct bio * bi)
(unsigned long long)new_sector, (unsigned long long)new_sector,
(unsigned long long)logical_sector); (unsigned long long)logical_sector);
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
sh = get_active_stripe(conf, new_sector, disks, 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 (sh) {
if (unlikely(conf->expand_progress != MaxSector)) { if (unlikely(conf->expand_progress != MaxSector)) {
...@@ -1877,6 +1884,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i ...@@ -1877,6 +1884,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
*/ */
int i; int i;
int dd_idx; int dd_idx;
sector_t writepos, safepos, gap;
if (sector_nr == 0 && if (sector_nr == 0 &&
conf->expand_progress != 0) { conf->expand_progress != 0) {
...@@ -1887,15 +1895,36 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i ...@@ -1887,15 +1895,36 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
return sector_nr; return sector_nr;
} }
/* Cannot proceed until we've updated the superblock... */ /* we update the metadata when there is more than 3Meg
wait_event(conf->wait_for_overlap, * in the block range (that is rather arbitrary, should
atomic_read(&conf->reshape_stripes)==0); * probably be time based) or when the data about to be
mddev->reshape_position = conf->expand_progress; * copied would over-write the source of the data at
* the front of the range.
mddev->sb_dirty = 1; * i.e. one new_stripe forward from expand_progress new_maps
md_wakeup_thread(mddev->thread); * to after where expand_lo old_maps to
wait_event(mddev->sb_wait, mddev->sb_dirty == 0 || */
kthread_should_stop()); writepos = conf->expand_progress +
conf->chunk_size/512*(conf->raid_disks-1);
sector_div(writepos, conf->raid_disks-1);
safepos = conf->expand_lo;
sector_div(safepos, conf->previous_raid_disks-1);
gap = conf->expand_progress - conf->expand_lo;
if (writepos >= safepos ||
gap > (conf->raid_disks-1)*3000*2 /*3Meg*/) {
/* Cannot proceed until we've updated the superblock... */
wait_event(conf->wait_for_overlap,
atomic_read(&conf->reshape_stripes)==0);
mddev->reshape_position = conf->expand_progress;
mddev->sb_dirty = 1;
md_wakeup_thread(mddev->thread);
wait_event(mddev->sb_wait, mddev->sb_dirty == 0 ||
kthread_should_stop());
spin_lock_irq(&conf->device_lock);
conf->expand_lo = mddev->reshape_position;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);
}
for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) { for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
int j; int j;
...@@ -2322,6 +2351,7 @@ static int run(mddev_t *mddev) ...@@ -2322,6 +2351,7 @@ static int run(mddev_t *mddev)
if (conf->expand_progress != MaxSector) { if (conf->expand_progress != MaxSector) {
printk("...ok start reshape thread\n"); printk("...ok start reshape thread\n");
conf->expand_lo = conf->expand_progress;
atomic_set(&conf->reshape_stripes, 0); atomic_set(&conf->reshape_stripes, 0);
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
...@@ -2610,6 +2640,7 @@ static int raid5_reshape(mddev_t *mddev, int raid_disks) ...@@ -2610,6 +2640,7 @@ static int raid5_reshape(mddev_t *mddev, int raid_disks)
conf->previous_raid_disks = conf->raid_disks; conf->previous_raid_disks = conf->raid_disks;
conf->raid_disks = raid_disks; conf->raid_disks = raid_disks;
conf->expand_progress = 0; conf->expand_progress = 0;
conf->expand_lo = 0;
spin_unlock_irq(&conf->device_lock); spin_unlock_irq(&conf->device_lock);
/* Add some new drives, as many as will fit. /* Add some new drives, as many as will fit.
......
...@@ -217,6 +217,9 @@ struct raid5_private_data { ...@@ -217,6 +217,9 @@ struct raid5_private_data {
/* used during an expand */ /* used during an expand */
sector_t expand_progress; /* MaxSector when no expand happening */ sector_t expand_progress; /* MaxSector when no expand happening */
sector_t expand_lo; /* from here up to expand_progress it out-of-bounds
* as we haven't flushed the metadata yet
*/
int previous_raid_disks; int previous_raid_disks;
struct list_head handle_list; /* stripes needing handling */ struct list_head handle_list; /* stripes needing handling */
......
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