Commit 6ba01df7 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm table: do not allow request-based DM to stack on partitions 



Partitioned request-based devices cannot be used as underlying devices
for request-based DM because no partition offsets are added to each
incoming request.  As such, until now, stacking on partitioned devices
would _always_ result in data corruption (e.g. wiping the partition
table, writing to other partitions, etc).  Fix this by disallowing
request-based stacking on partitions.

While at it, since all .request_fn support has been removed from block
core, remove legacy dm-table code that differentiated between blk-mq and
.request_fn request-based.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent a99d8080

drivers/md/dm-table.c

+8 −19
Original line number Diff line number Diff line
@@ -918,21 +918,15 @@ bool dm_table_supports_dax(struct dm_table *t, 


static bool dm_table_does_not_support_partial_completion(struct dm_table *t);



struct verify_rq_based_data {

	unsigned sq_count;

	unsigned mq_count;

};



static int device_is_rq_based(struct dm_target *ti, struct dm_dev *dev,

static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,

				  sector_t start, sector_t len, void *data)

{

	struct request_queue *q = bdev_get_queue(dev->bdev);

	struct verify_rq_based_data *v = data;

	struct block_device *bdev = dev->bdev;

	struct request_queue *q = bdev_get_queue(bdev);



	if (queue_is_mq(q))

		v->mq_count++;

	else

		v->sq_count++;

	/* request-based cannot stack on partitions! */

	if (bdev != bdev->bd_contains)

		return false;



	return queue_is_mq(q);

}
@@ -941,7 +935,6 @@ static int dm_table_determine_type(struct dm_table *t) 
{

	unsigned i;

	unsigned bio_based = 0, request_based = 0, hybrid = 0;

	struct verify_rq_based_data v = {.sq_count = 0, .mq_count = 0};

	struct dm_target *tgt;

	struct list_head *devices = dm_table_get_devices(t);

	enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
@@ -1045,14 +1038,10 @@ verify_rq_based: 


	/* Non-request-stackable devices can't be used for request-based dm */

	if (!tgt->type->iterate_devices ||

	    !tgt->type->iterate_devices(tgt, device_is_rq_based, &v)) {

	    !tgt->type->iterate_devices(tgt, device_is_rq_stackable, NULL)) {

		DMERR("table load rejected: including non-request-stackable devices");

		return -EINVAL;

	}

	if (v.sq_count > 0) {

		DMERR("table load rejected: not all devices are blk-mq request-stackable");

		return -EINVAL;

	}



	return 0;

}

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