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Commit 199dc6ed authored by NeilBrown's avatar NeilBrown
Browse files

md/raid0: update queue parameter in a safer location. 



When a (e.g.) RAID5 array is reshaped to RAID0, the updating
of queue parameters (e.g. max number of sectors per bio) is
done in the wrong place.
It should be part of ->run, but it is actually part of ->takeover.
This means it happens before level_store() calls:

	blk_set_stacking_limits(&mddev->queue->limits);

and so it ineffective.  This can lead to errors from underlying
devices.

So move all the relevant settings out of create_stripe_zones()
and into raid0_run().

As this can lead to a bug-on it is suitable for any -stable
kernel which supports reshape to RAID0.  So 2.6.35 or later.
As the bug has been present for five years there is no urgency,
so no need to rush into -stable.

Fixes: 9af204cf ("md: Add support for Raid5->Raid0 and Raid10->Raid0 takeover")
Cc: stable@vger.kernel.org (v2.6.35+ - please delay until after -final release).
Reported-by: default avatarYi Zhang <yizhan@redhat.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
parent 25eafe1a

drivers/md/raid0.c

+39 −36
Original line number Diff line number Diff line
@@ -83,7 +83,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
	char b[BDEVNAME_SIZE];

	char b2[BDEVNAME_SIZE];

	struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);

	bool discard_supported = false;

	unsigned short blksize = 512;



	if (!conf)

		return -ENOMEM;
@@ -98,6 +98,9 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
		sector_div(sectors, mddev->chunk_sectors);

		rdev1->sectors = sectors * mddev->chunk_sectors;



		blksize = max(blksize, queue_logical_block_size(

				      rdev1->bdev->bd_disk->queue));



		rdev_for_each(rdev2, mddev) {

			pr_debug("md/raid0:%s:   comparing %s(%llu)"

				 " with %s(%llu)\n",
@@ -134,6 +137,18 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
	}

	pr_debug("md/raid0:%s: FINAL %d zones\n",

		 mdname(mddev), conf->nr_strip_zones);

	/*

	 * now since we have the hard sector sizes, we can make sure

	 * chunk size is a multiple of that sector size

	 */

	if ((mddev->chunk_sectors << 9) % blksize) {

		printk(KERN_ERR "md/raid0:%s: chunk_size of %d not multiple of block size %d\n",

		       mdname(mddev),

		       mddev->chunk_sectors << 9, blksize);

		err = -EINVAL;

		goto abort;

	}



	err = -ENOMEM;

	conf->strip_zone = kzalloc(sizeof(struct strip_zone)*

				conf->nr_strip_zones, GFP_KERNEL);
@@ -188,19 +203,12 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
		}

		dev[j] = rdev1;



		if (mddev->queue)

			disk_stack_limits(mddev->gendisk, rdev1->bdev,

					  rdev1->data_offset << 9);



		if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)

			conf->has_merge_bvec = 1;



		if (!smallest || (rdev1->sectors < smallest->sectors))

			smallest = rdev1;

		cnt++;



		if (blk_queue_discard(bdev_get_queue(rdev1->bdev)))

			discard_supported = true;

	}

	if (cnt != mddev->raid_disks) {

		printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
@@ -261,28 +269,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
			 (unsigned long long)smallest->sectors);

	}



	/*

	 * now since we have the hard sector sizes, we can make sure

	 * chunk size is a multiple of that sector size

	 */

	if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {

		printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",

		       mdname(mddev),

		       mddev->chunk_sectors << 9);

		goto abort;

	}



	if (mddev->queue) {

		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);

		blk_queue_io_opt(mddev->queue,

				 (mddev->chunk_sectors << 9) * mddev->raid_disks);



		if (!discard_supported)

			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);

		else

			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);

	}



	pr_debug("md/raid0:%s: done.\n", mdname(mddev));

	*private_conf = conf;
@@ -433,12 +419,6 @@ static int raid0_run(struct mddev *mddev) 
	if (md_check_no_bitmap(mddev))

		return -EINVAL;



	if (mddev->queue) {

		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);

		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);

		blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);

	}



	/* if private is not null, we are here after takeover */

	if (mddev->private == NULL) {

		ret = create_strip_zones(mddev, &conf);
@@ -447,6 +427,29 @@ static int raid0_run(struct mddev *mddev) 
		mddev->private = conf;

	}

	conf = mddev->private;

	if (mddev->queue) {

		struct md_rdev *rdev;

		bool discard_supported = false;



		rdev_for_each(rdev, mddev) {

			disk_stack_limits(mddev->gendisk, rdev->bdev,

					  rdev->data_offset << 9);

			if (blk_queue_discard(bdev_get_queue(rdev->bdev)))

				discard_supported = true;

		}

		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);

		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);

		blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);



		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);

		blk_queue_io_opt(mddev->queue,

				 (mddev->chunk_sectors << 9) * mddev->raid_disks);



		if (!discard_supported)

			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);

		else

			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);

	}



	/* calculate array device size */

	md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));