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Commit 599cdf3b authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
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dm snapshot: allocate a per-target structure for snapshot-origin target 



Allocate a per-target dm_origin structure.  This is a prerequisite for
the next commit ("dm snapshot: do not split read bios sent to
snapshot-origin target") which adds a new member to this structure.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 1dd40c3e

drivers/md/dm-snap.c

+35 −18
Original line number Diff line number Diff line
@@ -2141,6 +2141,10 @@ static int origin_write_extent(struct dm_snapshot *merging_snap, 
 * Origin: maps a linear range of a device, with hooks for snapshotting.

 */



struct dm_origin {

	struct dm_dev *dev;

};



/*

 * Construct an origin mapping: <dev_path>

 * The context for an origin is merely a 'struct dm_dev *'
@@ -2149,41 +2153,54 @@ static int origin_write_extent(struct dm_snapshot *merging_snap, 
static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)

{

	int r;

	struct dm_dev *dev;

	struct dm_origin *o;



	if (argc != 1) {

		ti->error = "origin: incorrect number of arguments";

		return -EINVAL;

	}



	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);

	o = kmalloc(sizeof(struct dm_origin), GFP_KERNEL);

	if (!o) {

		ti->error = "Cannot allocate private origin structure";

		r = -ENOMEM;

		goto bad_alloc;

	}



	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &o->dev);

	if (r) {

		ti->error = "Cannot get target device";

		return r;

		goto bad_open;

	}



	ti->private = dev;

	ti->private = o;

	ti->num_flush_bios = 1;



	return 0;



bad_open:

	kfree(o);

bad_alloc:

	return r;

}



static void origin_dtr(struct dm_target *ti)

{

	struct dm_dev *dev = ti->private;

	dm_put_device(ti, dev);

	struct dm_origin *o = ti->private;

	dm_put_device(ti, o->dev);

	kfree(o);

}



static int origin_map(struct dm_target *ti, struct bio *bio)

{

	struct dm_dev *dev = ti->private;

	bio->bi_bdev = dev->bdev;

	struct dm_origin *o = ti->private;

	bio->bi_bdev = o->dev->bdev;



	if (bio->bi_rw & REQ_FLUSH)

		return DM_MAPIO_REMAPPED;



	/* Only tell snapshots if this is a write */

	return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;

	return (bio_rw(bio) == WRITE) ? do_origin(o->dev, bio) : DM_MAPIO_REMAPPED;

}



/*
@@ -2192,15 +2209,15 @@ static int origin_map(struct dm_target *ti, struct bio *bio) 
 */

static void origin_resume(struct dm_target *ti)

{

	struct dm_dev *dev = ti->private;

	struct dm_origin *o = ti->private;



	ti->max_io_len = get_origin_minimum_chunksize(dev->bdev);

	ti->max_io_len = get_origin_minimum_chunksize(o->dev->bdev);

}



static void origin_status(struct dm_target *ti, status_type_t type,

			  unsigned status_flags, char *result, unsigned maxlen)

{

	struct dm_dev *dev = ti->private;

	struct dm_origin *o = ti->private;



	switch (type) {

	case STATUSTYPE_INFO:
@@ -2208,7 +2225,7 @@ static void origin_status(struct dm_target *ti, status_type_t type, 
		break;



	case STATUSTYPE_TABLE:

		snprintf(result, maxlen, "%s", dev->name);

		snprintf(result, maxlen, "%s", o->dev->name);

		break;

	}

}
@@ -2216,13 +2233,13 @@ static void origin_status(struct dm_target *ti, status_type_t type, 
static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,

			struct bio_vec *biovec, int max_size)

{

	struct dm_dev *dev = ti->private;

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

	struct dm_origin *o = ti->private;

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



	if (!q->merge_bvec_fn)

		return max_size;



	bvm->bi_bdev = dev->bdev;

	bvm->bi_bdev = o->dev->bdev;



	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));

}
@@ -2230,9 +2247,9 @@ static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 
static int origin_iterate_devices(struct dm_target *ti,

				  iterate_devices_callout_fn fn, void *data)

{

	struct dm_dev *dev = ti->private;

	struct dm_origin *o = ti->private;



	return fn(ti, dev, 0, ti->len, data);

	return fn(ti, o->dev, 0, ti->len, data);

}



static struct target_type origin_target = {