md-cluster: Use a small window for resync

Suspending the entire device for resync could take too long. Resync
in small chunks.

cluster's resync window (32M) is maintained in r1conf as
cluster_sync_low and cluster_sync_high and processed in
raid1's sync_request(). If the current resync is outside the cluster
resync window:

1. Set the cluster_sync_low to curr_resync_completed.
2. Check if the sync will fit in the new window, if not issue a
   wait_barrier() and set cluster_sync_low to sector_nr.
3. Set cluster_sync_high to cluster_sync_low + resync_window.
4. Send a message to all nodes so they may add it in their suspension
   list.

bitmap_cond_end_sync is modified to allow to force a sync inorder
to get the curr_resync_completed uptodate with the sector passed.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/bitmap.c

@@ -1570,7 +1570,7 @@ void bitmap_close_sync(struct bitmap *bitmap)
 }
 EXPORT_SYMBOL(bitmap_close_sync);
 
-void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
+void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
 {
 	sector_t s = 0;
 	sector_t blocks;
@@ -1581,7 +1581,7 @@ void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
 		bitmap->last_end_sync = jiffies;
 		return;
 	}
-	if (time_before(jiffies, (bitmap->last_end_sync
+	if (!force && time_before(jiffies, (bitmap->last_end_sync
 				  + bitmap->mddev->bitmap_info.daemon_sleep)))
 		return;
 	wait_event(bitmap->mddev->recovery_wait,

drivers/md/bitmap.h

@@ -257,7 +257,7 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int degraded);
 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted);
 void bitmap_close_sync(struct bitmap *bitmap);
-void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector);
+void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force);
 
 void bitmap_unplug(struct bitmap *bitmap);
 void bitmap_daemon_work(struct mddev *mddev);

drivers/md/md-cluster.c

@@ -802,15 +802,6 @@ static int slot_number(struct mddev *mddev)
 	return cinfo->slot_number - 1;
 }
 
-static void resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
-{
-	struct md_cluster_info *cinfo = mddev->cluster_info;
-
-	add_resync_info(mddev, cinfo->bitmap_lockres, lo, hi);
-	/* Re-acquire the lock to refresh LVB */
-	dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW);
-}
-
 static int metadata_update_start(struct mddev *mddev)
 {
 	return lock_comm(mddev->cluster_info);
@@ -836,45 +827,25 @@ static int metadata_update_cancel(struct mddev *mddev)
 	return dlm_unlock_sync(cinfo->token_lockres);
 }
 
-static int resync_send(struct mddev *mddev, enum msg_type type,
-		sector_t lo, sector_t hi)
+static int resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
 {
 	struct md_cluster_info *cinfo = mddev->cluster_info;
 	struct cluster_msg cmsg;
 	int slot = cinfo->slot_number - 1;
 
+	add_resync_info(mddev, cinfo->bitmap_lockres, lo, hi);
+	/* Re-acquire the lock to refresh LVB */
+	dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW);
 	pr_info("%s:%d lo: %llu hi: %llu\n", __func__, __LINE__,
 			(unsigned long long)lo,
 			(unsigned long long)hi);
-	resync_info_update(mddev, lo, hi);
-	cmsg.type = cpu_to_le32(type);
+	cmsg.type = cpu_to_le32(RESYNCING);
 	cmsg.slot = cpu_to_le32(slot);
 	cmsg.low = cpu_to_le64(lo);
 	cmsg.high = cpu_to_le64(hi);
 	return sendmsg(cinfo, &cmsg);
 }
 
-static int resync_start(struct mddev *mddev, sector_t lo, sector_t hi)
-{
-	pr_info("%s:%d\n", __func__, __LINE__);
-	return resync_send(mddev, RESYNCING, lo, hi);
-}
-
-static void resync_finish(struct mddev *mddev)
-{
-	struct md_cluster_info *cinfo = mddev->cluster_info;
-	struct cluster_msg cmsg;
-	int slot = cinfo->slot_number - 1;
-
-	pr_info("%s:%d\n", __func__, __LINE__);
-	resync_send(mddev, RESYNCING, 0, 0);
-	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
-		cmsg.type = cpu_to_le32(BITMAP_NEEDS_SYNC);
-		cmsg.slot = cpu_to_le32(slot);
-		sendmsg(cinfo, &cmsg);
-	}
-}
-
 static int area_resyncing(struct mddev *mddev, int direction,
 		sector_t lo, sector_t hi)
 {
@@ -997,8 +968,6 @@ static struct md_cluster_operations cluster_ops = {
 	.leave  = leave,
 	.slot_number = slot_number,
 	.resync_info_update = resync_info_update,
-	.resync_start = resync_start,
-	.resync_finish = resync_finish,
 	.metadata_update_start = metadata_update_start,
 	.metadata_update_finish = metadata_update_finish,
 	.metadata_update_cancel = metadata_update_cancel,

drivers/md/md-cluster.h

@@ -12,9 +12,7 @@ struct md_cluster_operations {
 	int (*join)(struct mddev *mddev, int nodes);
 	int (*leave)(struct mddev *mddev);
 	int (*slot_number)(struct mddev *mddev);
-	void (*resync_info_update)(struct mddev *mddev, sector_t lo, sector_t hi);
-	int (*resync_start)(struct mddev *mddev, sector_t lo, sector_t hi);
-	void (*resync_finish)(struct mddev *mddev);
+	int (*resync_info_update)(struct mddev *mddev, sector_t lo, sector_t hi);
 	int (*metadata_update_start)(struct mddev *mddev);
 	int (*metadata_update_finish)(struct mddev *mddev);
 	int (*metadata_update_cancel)(struct mddev *mddev);

drivers/md/md.c

@@ -7805,9 +7805,6 @@ void md_do_sync(struct md_thread *thread)
 	md_new_event(mddev);
 	update_time = jiffies;
 
-	if (mddev_is_clustered(mddev))
-		md_cluster_ops->resync_start(mddev, j, max_sectors);
-
 	blk_start_plug(&plug);
 	while (j < max_sectors) {
 		sector_t sectors;
@@ -7871,8 +7868,6 @@ void md_do_sync(struct md_thread *thread)
 			j = max_sectors;
 		if (j > 2)
 			mddev->curr_resync = j;
-		if (mddev_is_clustered(mddev))
-			md_cluster_ops->resync_info_update(mddev, j, max_sectors);
 		mddev->curr_mark_cnt = io_sectors;
 		if (last_check == 0)
 			/* this is the earliest that rebuild will be
@@ -7979,9 +7974,6 @@ void md_do_sync(struct md_thread *thread)
 		}
 	}
  skip:
-	if (mddev_is_clustered(mddev))
-		md_cluster_ops->resync_finish(mddev);
-
 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
 
 	spin_lock(&mddev->lock);

drivers/md/raid1.c

@@ -90,6 +90,8 @@ static void r1bio_pool_free(void *r1_bio, void *data)
 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
 #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
 #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
+#define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
+#define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
 #define NEXT_NORMALIO_DISTANCE (3 * RESYNC_WINDOW_SECTORS)
 
 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
@@ -2488,6 +2490,13 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
 
 		bitmap_close_sync(mddev->bitmap);
 		close_sync(conf);
+
+		if (mddev_is_clustered(mddev)) {
+			conf->cluster_sync_low = 0;
+			conf->cluster_sync_high = 0;
+			/* Send zeros to mark end of resync */
+			md_cluster_ops->resync_info_update(mddev, 0, 0);
+		}
 		return 0;
 	}
 
@@ -2508,7 +2517,12 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
 		return sync_blocks;
 	}
 
-	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
+	/* we are incrementing sector_nr below. To be safe, we check against
+	 * sector_nr + two times RESYNC_SECTORS
+	 */
+
+	bitmap_cond_end_sync(mddev->bitmap, sector_nr,
+		mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
 	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
 
 	raise_barrier(conf, sector_nr);
@@ -2699,6 +2713,16 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
  bio_full:
 	r1_bio->sectors = nr_sectors;
 
+	if (mddev_is_clustered(mddev) &&
+			conf->cluster_sync_high < sector_nr + nr_sectors) {
+		conf->cluster_sync_low = mddev->curr_resync_completed;
+		conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
+		/* Send resync message */
+		md_cluster_ops->resync_info_update(mddev,
+				conf->cluster_sync_low,
+				conf->cluster_sync_high);
+	}
+
 	/* For a user-requested sync, we read all readable devices and do a
 	 * compare
 	 */

drivers/md/raid1.h

@@ -111,6 +111,13 @@ struct r1conf {
 	 * the new thread here until we fully activate the array.
 	 */
 	struct md_thread	*thread;
+
+	/* Keep track of cluster resync window to send to other
+	 * nodes.
+	 */
+	sector_t		cluster_sync_low;
+	sector_t		cluster_sync_high;
+
 };
 
 /*

drivers/md/raid10.c

@@ -3137,7 +3137,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 		/* resync. Schedule a read for every block at this virt offset */
 		int count = 0;
 
-		bitmap_cond_end_sync(mddev->bitmap, sector_nr);
+		bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
 
 		if (!bitmap_start_sync(mddev->bitmap, sector_nr,
 				       &sync_blocks, mddev->degraded) &&

drivers/md/raid5.c

@@ -5613,7 +5613,7 @@ static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int
 		return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
 	}
 
-	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
+	bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
 
 	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
 	if (sh == NULL) {