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Commit eb3b2d6b authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: factor out get_parent_info() 



In preparation for the new parent_get and parent_overlap_get class
methods, factor out the fetching and decoding of parent data.

As a side effect, we now decode all four fields in the "no parent"
case.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarJason Dillaman <dillaman@redhat.com>
parent 8aaff151

drivers/block/rbd.c

+86 −48
Original line number Diff line number Diff line
@@ -4584,47 +4584,95 @@ static int rbd_dev_v2_features(struct rbd_device *rbd_dev) 
						&rbd_dev->header.features);

}



static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)

{

	struct rbd_spec *parent_spec;

	size_t size;

	void *reply_buf = NULL;

	__le64 snapid;

	void *p;

	void *end;

struct parent_image_info {

	u64		pool_id;

	char *image_id;

	const char	*image_id;

	u64		snap_id;



	u64		overlap;

};



/*

 * The caller is responsible for @pii.

 */

static int __get_parent_info_legacy(struct rbd_device *rbd_dev,

				    struct page *req_page,

				    struct page *reply_page,

				    struct parent_image_info *pii)

{

	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;

	size_t reply_len = PAGE_SIZE;

	void *p, *end;

	int ret;



	ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,

			     "rbd", "get_parent", CEPH_OSD_FLAG_READ,

			     req_page, sizeof(u64), reply_page, &reply_len);

	if (ret)

		return ret;



	p = page_address(reply_page);

	end = p + reply_len;

	ceph_decode_64_safe(&p, end, pii->pool_id, e_inval);

	pii->image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);

	if (IS_ERR(pii->image_id)) {

		ret = PTR_ERR(pii->image_id);

		pii->image_id = NULL;

		return ret;

	}

	ceph_decode_64_safe(&p, end, pii->snap_id, e_inval);

	ceph_decode_64_safe(&p, end, pii->overlap, e_inval);



	return 0;



e_inval:

	return -EINVAL;

}



static int get_parent_info(struct rbd_device *rbd_dev,

			   struct parent_image_info *pii)

{

	struct page *req_page, *reply_page;

	void *p;

	int ret;



	req_page = alloc_page(GFP_KERNEL);

	if (!req_page)

		return -ENOMEM;



	reply_page = alloc_page(GFP_KERNEL);

	if (!reply_page) {

		__free_page(req_page);

		return -ENOMEM;

	}



	p = page_address(req_page);

	ceph_encode_64(&p, rbd_dev->spec->snap_id);

	ret = __get_parent_info_legacy(rbd_dev, req_page, reply_page, pii);



	__free_page(req_page);

	__free_page(reply_page);

	return ret;

}



static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)

{

	struct rbd_spec *parent_spec;

	struct parent_image_info pii = { 0 };

	int ret;



	parent_spec = rbd_spec_alloc();

	if (!parent_spec)

		return -ENOMEM;



	size = sizeof (__le64) +				/* pool_id */

		sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX +	/* image_id */

		sizeof (__le64) +				/* snap_id */

		sizeof (__le64);				/* overlap */

	reply_buf = kmalloc(size, GFP_KERNEL);

	if (!reply_buf) {

		ret = -ENOMEM;

	ret = get_parent_info(rbd_dev, &pii);

	if (ret)

		goto out_err;

	}



	snapid = cpu_to_le64(rbd_dev->spec->snap_id);

	ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,

				  &rbd_dev->header_oloc, "get_parent",

				  &snapid, sizeof(snapid), reply_buf, size);

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

	if (ret < 0)

		goto out_err;

	dout("%s pool_id %llu image_id %s snap_id %llu overlap %llu\n",

	     __func__, pii.pool_id, pii.image_id, pii.snap_id, pii.overlap);



	p = reply_buf;

	end = reply_buf + ret;

	ret = -ERANGE;

	ceph_decode_64_safe(&p, end, pool_id, out_err);

	if (pool_id == CEPH_NOPOOL) {

	if (pii.pool_id == CEPH_NOPOOL) {

		/*

		 * Either the parent never existed, or we have

		 * record of it but the image got flattened so it no
@@ -4647,19 +4695,11 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
	/* The ceph file layout needs to fit pool id in 32 bits */



	ret = -EIO;

	if (pool_id > (u64)U32_MAX) {

	if (pii.pool_id > (u64)U32_MAX) {

		rbd_warn(NULL, "parent pool id too large (%llu > %u)",

			(unsigned long long)pool_id, U32_MAX);

		goto out_err;

	}



	image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);

	if (IS_ERR(image_id)) {

		ret = PTR_ERR(image_id);

			(unsigned long long)pii.pool_id, U32_MAX);

		goto out_err;

	}

	ceph_decode_64_safe(&p, end, snap_id, out_err);

	ceph_decode_64_safe(&p, end, overlap, out_err);



	/*

	 * The parent won't change (except when the clone is
@@ -4667,9 +4707,10 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
	 * record the parent spec we have not already done so.

	 */

	if (!rbd_dev->parent_spec) {

		parent_spec->pool_id = pool_id;

		parent_spec->image_id = image_id;

		parent_spec->snap_id = snap_id;

		parent_spec->pool_id = pii.pool_id;

		parent_spec->image_id = pii.image_id;

		pii.image_id = NULL;

		parent_spec->snap_id = pii.snap_id;



		/* TODO: support cloning across namespaces */

		if (rbd_dev->spec->pool_ns) {
@@ -4683,15 +4724,13 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 


		rbd_dev->parent_spec = parent_spec;

		parent_spec = NULL;	/* rbd_dev now owns this */

	} else {

		kfree(image_id);

	}



	/*

	 * We always update the parent overlap.  If it's zero we issue

	 * a warning, as we will proceed as if there was no parent.

	 */

	if (!overlap) {

	if (!pii.overlap) {

		if (parent_spec) {

			/* refresh, careful to warn just once */

			if (rbd_dev->parent_overlap)
@@ -4702,14 +4741,13 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
			rbd_warn(rbd_dev, "clone is standalone (overlap 0)");

		}

	}

	rbd_dev->parent_overlap = overlap;

	rbd_dev->parent_overlap = pii.overlap;



out:

	ret = 0;

out_err:

	kfree(reply_buf);

	kfree(pii.image_id);

	rbd_spec_put(parent_spec);



	return ret;

}