Commit 1e130199 authored by Alex Elder's avatar Alex Elder
Browse files

rbd: get the object prefix for a v2 rbd image 



The object prefix of an rbd format 2 image is fetched from the
server using a "get_object_prefix" method.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 9d475de5

drivers/block/rbd.c

+47 −1
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ 
#define RBD_SNAP_HEAD_NAME	"-"



#define RBD_IMAGE_ID_LEN_MAX	64

#define RBD_OBJ_PREFIX_LEN_MAX	64



/*

 * An RBD device name will be "rbd#", where the "rbd" comes from
@@ -2168,6 +2169,43 @@ static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev) 
					&rbd_dev->header.image_size);

}



static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)

{

	void *reply_buf;

	int ret;

	void *p;



	reply_buf = kzalloc(RBD_OBJ_PREFIX_LEN_MAX, GFP_KERNEL);

	if (!reply_buf)

		return -ENOMEM;



	ret = rbd_req_sync_exec(rbd_dev, rbd_dev->header_name,

				"rbd", "get_object_prefix",

				NULL, 0,

				reply_buf, RBD_OBJ_PREFIX_LEN_MAX,

				CEPH_OSD_FLAG_READ, NULL);

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

	if (ret < 0)

		goto out;



	p = reply_buf;

	rbd_dev->header.object_prefix = ceph_extract_encoded_string(&p,

						p + RBD_OBJ_PREFIX_LEN_MAX,

						NULL, GFP_NOIO);



	if (IS_ERR(rbd_dev->header.object_prefix)) {

		ret = PTR_ERR(rbd_dev->header.object_prefix);

		rbd_dev->header.object_prefix = NULL;

	} else {

		dout("  object_prefix = %s\n", rbd_dev->header.object_prefix);

	}



out:

	kfree(reply_buf);



	return ret;

}



/*

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

 * newly-received snapshot context.  Remove any existing snapshots
@@ -2693,6 +2731,12 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev) 
	/* Get the size and object order for the image */



	ret = rbd_dev_v2_image_size(rbd_dev);

	if (ret < 0)

		goto out_err;



	/* Get the object prefix (a.k.a. block_name) for the image */



	ret = rbd_dev_v2_object_prefix(rbd_dev);

	if (ret < 0)

		goto out_err;

	rbd_dev->image_format = 2;
@@ -2704,6 +2748,8 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev) 
out_err:

	kfree(rbd_dev->header_name);

	rbd_dev->header_name = NULL;

	kfree(rbd_dev->header.object_prefix);

	rbd_dev->header.object_prefix = NULL;



	return ret;

}