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Commit 9d475de5 authored by Alex Elder's avatar Alex Elder
Browse files

rbd: add code to get the size of a v2 rbd image 



The size of an rbd format 2 image is fetched from the server using a
"get_size" method.  The same method is used for getting the size of
a snapshot, so structure this addition with a generic helper routine
that we can get this information for either.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent a30b71b9

drivers/block/rbd.c

+53 −0
Original line number Diff line number Diff line
@@ -2127,6 +2127,47 @@ static char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which, 
	return snap_name;

}



/*

 * Get the size and object order for an image snapshot, or if

 * snap_id is CEPH_NOSNAP, gets this information for the base

 * image.

 */

static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,

				u8 *order, u64 *snap_size)

{

	__le64 snapid = cpu_to_le64(snap_id);

	int ret;

	struct {

		u8 order;

		__le64 size;

	} __attribute__ ((packed)) size_buf = { 0 };



	ret = rbd_req_sync_exec(rbd_dev, rbd_dev->header_name,

				"rbd", "get_size",

				(char *) &snapid, sizeof (snapid),

				(char *) &size_buf, sizeof (size_buf),

				CEPH_OSD_FLAG_READ, NULL);

	dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret);

	if (ret < 0)

		return ret;



	*order = size_buf.order;

	*snap_size = le64_to_cpu(size_buf.size);



	dout("  snap_id 0x%016llx order = %u, snap_size = %llu\n",

		(unsigned long long) snap_id, (unsigned int) *order,

		(unsigned long long) *snap_size);



	return 0;

}



static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)

{

	return _rbd_dev_v2_snap_size(rbd_dev, CEPH_NOSNAP,

					&rbd_dev->header.obj_order,

					&rbd_dev->header.image_size);

}



/*

 * Scan the rbd device's current snapshot list and compare it to the

 * newly-received snapshot context.  Remove any existing snapshots
@@ -2636,6 +2677,7 @@ static int rbd_dev_v1_probe(struct rbd_device *rbd_dev) 
static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)

{

	size_t size;

	int ret;



	/*

	 * Image id was filled in by the caller.  Record the header
@@ -2647,12 +2689,23 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev) 
		return -ENOMEM;

	sprintf(rbd_dev->header_name, "%s%s",

			RBD_HEADER_PREFIX, rbd_dev->image_id);



	/* Get the size and object order for the image */



	ret = rbd_dev_v2_image_size(rbd_dev);

	if (ret < 0)

		goto out_err;

	rbd_dev->image_format = 2;



	dout("discovered version 2 image, header name is %s\n",

		rbd_dev->header_name);



	return -ENOTSUPP;

out_err:

	kfree(rbd_dev->header_name);

	rbd_dev->header_name = NULL;



	return ret;

}



/*