md/raid5: refactor raid5 "run"

.. so that the code to create the private data structures is separate.
This will help with future code to change the level of an active
array.

Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/raid5.c

@@ -4164,33 +4164,147 @@ static struct attribute_group raid5_attrs_group = {
 	.attrs = raid5_attrs,
 };
 
-static int run(mddev_t *mddev)
+static raid5_conf_t *setup_conf(mddev_t *mddev)
 {
 	raid5_conf_t *conf;
 	int raid_disk, memory;
 	mdk_rdev_t *rdev;
 	struct disk_info *disk;
-	int working_disks = 0;
 
-	if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
+	if (mddev->new_level != 5
+	    && mddev->new_level != 4
+	    && mddev->new_level != 6) {
 		printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
-		       mdname(mddev), mddev->level);
+		       mdname(mddev), mddev->new_level);
-		return -EIO;
+		return ERR_PTR(-EIO);
 	}
-	if ((mddev->level == 5 && !algorithm_valid_raid5(mddev->layout)) ||
+	if ((mddev->new_level == 5
-	    (mddev->level == 6 && !algorithm_valid_raid6(mddev->layout))) {
+	     && !algorithm_valid_raid5(mddev->new_layout)) ||
+	    (mddev->new_level == 6
+	     && !algorithm_valid_raid6(mddev->new_layout))) {
 		printk(KERN_ERR "raid5: %s: layout %d not supported\n",
-		       mdname(mddev), mddev->layout);
+		       mdname(mddev), mddev->new_layout);
-		return -EIO;
+		return ERR_PTR(-EIO);
+	}
+	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
+		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
+		       mdname(mddev), mddev->raid_disks);
+		return ERR_PTR(-EINVAL);
 	}
 
-	if (mddev->chunk_size < PAGE_SIZE) {
+	if (!mddev->new_chunk || mddev->new_chunk % PAGE_SIZE) {
-		printk(KERN_ERR "md/raid5: chunk_size must be at least "
+		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
-		       "PAGE_SIZE but %d < %ld\n",
+			mddev->new_chunk, mdname(mddev));
-		       mddev->chunk_size, PAGE_SIZE);
+		return ERR_PTR(-EINVAL);
-		return -EINVAL;
 	}
 
+	conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
+	if (conf == NULL)
+		goto abort;
+
+	conf->raid_disks = mddev->raid_disks;
+	if (mddev->reshape_position == MaxSector)
+		conf->previous_raid_disks = mddev->raid_disks;
+	else
+		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
+
+	conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
+			      GFP_KERNEL);
+	if (!conf->disks)
+		goto abort;
+
+	conf->mddev = mddev;
+
+	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
+		goto abort;
+
+	if (mddev->new_level == 6) {
+		conf->spare_page = alloc_page(GFP_KERNEL);
+		if (!conf->spare_page)
+			goto abort;
+	}
+	spin_lock_init(&conf->device_lock);
+	init_waitqueue_head(&conf->wait_for_stripe);
+	init_waitqueue_head(&conf->wait_for_overlap);
+	INIT_LIST_HEAD(&conf->handle_list);
+	INIT_LIST_HEAD(&conf->hold_list);
+	INIT_LIST_HEAD(&conf->delayed_list);
+	INIT_LIST_HEAD(&conf->bitmap_list);
+	INIT_LIST_HEAD(&conf->inactive_list);
+	atomic_set(&conf->active_stripes, 0);
+	atomic_set(&conf->preread_active_stripes, 0);
+	atomic_set(&conf->active_aligned_reads, 0);
+	conf->bypass_threshold = BYPASS_THRESHOLD;
+
+	pr_debug("raid5: run(%s) called.\n", mdname(mddev));
+
+	list_for_each_entry(rdev, &mddev->disks, same_set) {
+		raid_disk = rdev->raid_disk;
+		if (raid_disk >= conf->raid_disks
+		    || raid_disk < 0)
+			continue;
+		disk = conf->disks + raid_disk;
+
+		disk->rdev = rdev;
+
+		if (test_bit(In_sync, &rdev->flags)) {
+			char b[BDEVNAME_SIZE];
+			printk(KERN_INFO "raid5: device %s operational as raid"
+				" disk %d\n", bdevname(rdev->bdev,b),
+				raid_disk);
+		} else
+			/* Cannot rely on bitmap to complete recovery */
+			conf->fullsync = 1;
+	}
+
+	conf->chunk_size = mddev->new_chunk;
+	conf->level = mddev->new_level;
+	if (conf->level == 6)
+		conf->max_degraded = 2;
+	else
+		conf->max_degraded = 1;
+	conf->algorithm = mddev->new_layout;
+	conf->max_nr_stripes = NR_STRIPES;
+	conf->expand_progress = mddev->reshape_position;
+
+	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
+		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
+	if (grow_stripes(conf, conf->max_nr_stripes)) {
+		printk(KERN_ERR
+			"raid5: couldn't allocate %dkB for buffers\n", memory);
+		goto abort;
+	} else
+		printk(KERN_INFO "raid5: allocated %dkB for %s\n",
+			memory, mdname(mddev));
+
+	conf->thread = md_register_thread(raid5d, mddev, "%s_raid5");
+	if (!conf->thread) {
+		printk(KERN_ERR
+		       "raid5: couldn't allocate thread for %s\n",
+		       mdname(mddev));
+		goto abort;
+	}
+
+	return conf;
+
+ abort:
+	if (conf) {
+		shrink_stripes(conf);
+		safe_put_page(conf->spare_page);
+		kfree(conf->disks);
+		kfree(conf->stripe_hashtbl);
+		kfree(conf);
+		return ERR_PTR(-EIO);
+	} else
+		return ERR_PTR(-ENOMEM);
+}
+
+static int run(mddev_t *mddev)
+{
+	raid5_conf_t *conf;
+	int working_disks = 0;
+	mdk_rdev_t *rdev;
+
 	if (mddev->reshape_position != MaxSector) {
 		/* Check that we can continue the reshape.
 		 * Currently only disks can change, it must
@@ -4241,99 +4355,33 @@ static int run(mddev_t *mddev)
 		}
 		printk(KERN_INFO "raid5: reshape will continue\n");
 		/* OK, we should be able to continue; */
-	}
-
-
-	mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
-	if ((conf = mddev->private) == NULL)
-		goto abort;
-	if (mddev->reshape_position == MaxSector) {
-		conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
 	} else {
-		conf->raid_disks = mddev->raid_disks;
+		BUG_ON(mddev->level != mddev->new_level);
-		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
+		BUG_ON(mddev->layout != mddev->new_layout);
+		BUG_ON(mddev->chunk_size != mddev->new_chunk);
+		BUG_ON(mddev->delta_disks != 0);
 	}
+	conf = setup_conf(mddev);
 
-	conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
+	if (conf == NULL)
-			      GFP_KERNEL);
+		return -EIO;
-	if (!conf->disks)
+	if (IS_ERR(conf))
-		goto abort;
+		return PTR_ERR(conf);
 
-	conf->mddev = mddev;
+	mddev->thread = conf->thread;
-
+	conf->thread = NULL;
-	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
+	mddev->private = conf;
-		goto abort;
-
-	if (mddev->level == 6) {
-		conf->spare_page = alloc_page(GFP_KERNEL);
-		if (!conf->spare_page)
-			goto abort;
-	}
-	spin_lock_init(&conf->device_lock);
-	mddev->queue->queue_lock = &conf->device_lock;
-	init_waitqueue_head(&conf->wait_for_stripe);
-	init_waitqueue_head(&conf->wait_for_overlap);
-	INIT_LIST_HEAD(&conf->handle_list);
-	INIT_LIST_HEAD(&conf->hold_list);
-	INIT_LIST_HEAD(&conf->delayed_list);
-	INIT_LIST_HEAD(&conf->bitmap_list);
-	INIT_LIST_HEAD(&conf->inactive_list);
-	atomic_set(&conf->active_stripes, 0);
-	atomic_set(&conf->preread_active_stripes, 0);
-	atomic_set(&conf->active_aligned_reads, 0);
-	conf->bypass_threshold = BYPASS_THRESHOLD;
-
-	pr_debug("raid5: run(%s) called.\n", mdname(mddev));
-
-	list_for_each_entry(rdev, &mddev->disks, same_set) {
-		raid_disk = rdev->raid_disk;
-		if (raid_disk >= conf->raid_disks
-		    || raid_disk < 0)
-			continue;
-		disk = conf->disks + raid_disk;
-
-		disk->rdev = rdev;
-
-		if (test_bit(In_sync, &rdev->flags)) {
-			char b[BDEVNAME_SIZE];
-			printk(KERN_INFO "raid5: device %s operational as raid"
-				" disk %d\n", bdevname(rdev->bdev,b),
-				raid_disk);
-			working_disks++;
-		} else
-			/* Cannot rely on bitmap to complete recovery */
-			conf->fullsync = 1;
-	}
 
 	/*
 	 * 0 for a fully functional array, 1 or 2 for a degraded array.
 	 */
+	list_for_each_entry(rdev, &mddev->disks, same_set)
+		if (rdev->raid_disk >= 0 &&
+		    test_bit(In_sync, &rdev->flags))
+			working_disks++;
+
 	mddev->degraded = conf->raid_disks - working_disks;
-	conf->mddev = mddev;
-	conf->chunk_size = mddev->chunk_size;
-	conf->level = mddev->level;
-	if (conf->level == 6)
-		conf->max_degraded = 2;
-	else
-		conf->max_degraded = 1;
-	conf->algorithm = mddev->layout;
-	conf->max_nr_stripes = NR_STRIPES;
-	conf->expand_progress = mddev->reshape_position;
 
-	/* device size must be a multiple of chunk size */
-	mddev->dev_sectors &= ~(mddev->chunk_size / 512 - 1);
-	mddev->resync_max_sectors = mddev->dev_sectors;
-
-	if (conf->level == 6 && conf->raid_disks < 4) {
-		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
-		       mdname(mddev), conf->raid_disks);
-		goto abort;
-	}
-	if (!conf->chunk_size || conf->chunk_size % 4) {
-		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
-			conf->chunk_size, mdname(mddev));
-		goto abort;
-	}
 	if (mddev->degraded > conf->max_degraded) {
 		printk(KERN_ERR "raid5: not enough operational devices for %s"
 			" (%d/%d failed)\n",
@@ -4341,6 +4389,10 @@ static int run(mddev_t *mddev)
 		goto abort;
 	}
 
+	/* device size must be a multiple of chunk size */
+	mddev->dev_sectors &= ~(mddev->chunk_size / 512 - 1);
+	mddev->resync_max_sectors = mddev->dev_sectors;
+
 	if (mddev->degraded > 0 &&
 	    mddev->recovery_cp != MaxSector) {
 		if (mddev->ok_start_degraded)
@@ -4356,27 +4408,6 @@ static int run(mddev_t *mddev)
 		}
 	}
 
-	{
-		mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
-		if (!mddev->thread) {
-			printk(KERN_ERR 
-				"raid5: couldn't allocate thread for %s\n",
-				mdname(mddev));
-			goto abort;
-		}
-	}
-	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
-		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
-	if (grow_stripes(conf, conf->max_nr_stripes)) {
-		printk(KERN_ERR 
-			"raid5: couldn't allocate %dkB for buffers\n", memory);
-		shrink_stripes(conf);
-		md_unregister_thread(mddev->thread);
-		goto abort;
-	} else
-		printk(KERN_INFO "raid5: allocated %dkB for %s\n",
-			memory, mdname(mddev));
-
 	if (mddev->degraded == 0)
 		printk("raid5: raid level %d set %s active with %d out of %d"
 			" devices, algorithm %d\n", conf->level, mdname(mddev), 
@@ -4419,6 +4450,8 @@ static int run(mddev_t *mddev)
 		       "raid5: failed to create sysfs attributes for %s\n",
 		       mdname(mddev));
 
+	mddev->queue->queue_lock = &conf->device_lock;
+
 	mddev->queue->unplug_fn = raid5_unplug_device;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	mddev->queue->backing_dev_info.congested_fn = raid5_congested;
@@ -4430,7 +4463,11 @@ static int run(mddev_t *mddev)
 
 	return 0;
 abort:
+	if (mddev->thread)
+		md_unregister_thread(mddev->thread);
+	mddev->thread = NULL;
 	if (conf) {
+		shrink_stripes(conf);
 		print_raid5_conf(conf);
 		safe_put_page(conf->spare_page);
 		kfree(conf->disks);

drivers/md/raid5.h

@@ -386,6 +386,11 @@ struct raid5_private_data {
 	int			pool_size; /* number of disks in stripeheads in pool */
 	spinlock_t		device_lock;
 	struct disk_info	*disks;
+
+	/* When taking over an array from a different personality, we store
+	 * the new thread here until we fully activate the array.
+	 */
+	struct mdk_thread_s	*thread;
 };
 
 typedef struct raid5_private_data raid5_conf_t;