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Commit bc2a3044 authored by Ilya Dryomov's avatar Ilya Dryomov Committed by Greg Kroah-Hartman
Browse files

rbd: decouple parent info read-in from updating rbd_dev 



commit c10311776f0a8ddea2276df96e255625b07045a8 upstream.

Unlike header read-in, parent info read-in is already decoupled in
get_parent_info(), but it's buried in rbd_dev_v2_parent_info() along
with the processing logic.

Separate the initial read-in and update read-in logic into
rbd_dev_setup_parent() and rbd_dev_update_parent() respectively and
have rbd_dev_v2_parent_info() just populate struct parent_image_info
(i.e. what get_parent_info() did).  Some existing QoI issues, like
flatten of a standalone clone being disregarded on refresh, remain.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarDongsheng Yang <dongsheng.yang@easystack.cn>
[idryomov@gmail.com: backport to 5.4: context]
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 2e0114ed

drivers/block/rbd.c

+80 −62
Original line number Diff line number Diff line
@@ -5762,6 +5762,14 @@ struct parent_image_info { 
	u64		overlap;

};



static void rbd_parent_info_cleanup(struct parent_image_info *pii)

{

	kfree(pii->pool_ns);

	kfree(pii->image_id);



	memset(pii, 0, sizeof(*pii));

}



/*

 * The caller is responsible for @pii.

 */
@@ -5831,6 +5839,9 @@ static int __get_parent_info(struct rbd_device *rbd_dev, 
	if (pii->has_overlap)

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



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

	     __func__, pii->pool_id, pii->pool_ns, pii->image_id, pii->snap_id,

	     pii->has_overlap, pii->overlap);

	return 0;



e_inval:
@@ -5869,13 +5880,16 @@ static int __get_parent_info_legacy(struct rbd_device *rbd_dev, 
	pii->has_overlap = true;

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



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

	     __func__, pii->pool_id, pii->pool_ns, pii->image_id, pii->snap_id,

	     pii->has_overlap, pii->overlap);

	return 0;



e_inval:

	return -EINVAL;

}



static int get_parent_info(struct rbd_device *rbd_dev,

static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev,

				  struct parent_image_info *pii)

{

	struct page *req_page, *reply_page;
@@ -5904,7 +5918,7 @@ static int get_parent_info(struct rbd_device *rbd_dev, 
	return ret;

}



static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)

static int rbd_dev_setup_parent(struct rbd_device *rbd_dev)

{

	struct rbd_spec *parent_spec;

	struct parent_image_info pii = { 0 };
@@ -5914,37 +5928,12 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
	if (!parent_spec)

		return -ENOMEM;



	ret = get_parent_info(rbd_dev, &pii);

	ret = rbd_dev_v2_parent_info(rbd_dev, &pii);

	if (ret)

		goto out_err;



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

	     __func__, pii.pool_id, pii.pool_ns, pii.image_id, pii.snap_id,

	     pii.has_overlap, pii.overlap);



	if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap) {

		/*

		 * Either the parent never existed, or we have

		 * record of it but the image got flattened so it no

		 * longer has a parent.  When the parent of a

		 * layered image disappears we immediately set the

		 * overlap to 0.  The effect of this is that all new

		 * requests will be treated as if the image had no

		 * parent.

		 *

		 * If !pii.has_overlap, the parent image spec is not

		 * applicable.  It's there to avoid duplication in each

		 * snapshot record.

		 */

		if (rbd_dev->parent_overlap) {

			rbd_dev->parent_overlap = 0;

			rbd_dev_parent_put(rbd_dev);

			pr_info("%s: clone image has been flattened\n",

				rbd_dev->disk->disk_name);

		}



	if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap)

		goto out;	/* No parent?  No problem. */

	}



	/* The ceph file layout needs to fit pool id in 32 bits */
@@ -5956,11 +5945,9 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
	}



	/*

	 * The parent won't change (except when the clone is

	 * flattened, already handled that).  So we only need to

	 * record the parent spec we have not already done so.

	 * The parent won't change except when the clone is flattened,

	 * so we only need to record the parent image spec once.

	 */

	if (!rbd_dev->parent_spec) {

	parent_spec->pool_id = pii.pool_id;

	if (pii.pool_ns && *pii.pool_ns) {

		parent_spec->pool_ns = pii.pool_ns;
@@ -5970,32 +5957,22 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev) 
	pii.image_id = NULL;

	parent_spec->snap_id = pii.snap_id;



	rbd_assert(!rbd_dev->parent_spec);

	rbd_dev->parent_spec = parent_spec;

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

	}



	/*

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

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

	 * Record the parent overlap.  If it's zero, issue a warning as

	 * we will proceed as if there is no parent.

	 */

	if (!pii.overlap) {

		if (parent_spec) {

			/* refresh, careful to warn just once */

			if (rbd_dev->parent_overlap)

				rbd_warn(rbd_dev,

				    "clone now standalone (overlap became 0)");

		} else {

			/* initial probe */

	if (!pii.overlap)

		rbd_warn(rbd_dev, "clone is standalone (overlap 0)");

		}

	}

	rbd_dev->parent_overlap = pii.overlap;



out:

	ret = 0;

out_err:

	kfree(pii.pool_ns);

	kfree(pii.image_id);

	rbd_parent_info_cleanup(&pii);

	rbd_spec_put(parent_spec);

	return ret;

}
@@ -6992,7 +6969,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth) 
	}



	if (rbd_dev->header.features & RBD_FEATURE_LAYERING) {

		ret = rbd_dev_v2_parent_info(rbd_dev);

		ret = rbd_dev_setup_parent(rbd_dev);

		if (ret)

			goto err_out_probe;

	}
@@ -7041,9 +7018,47 @@ static void rbd_dev_update_header(struct rbd_device *rbd_dev, 
	}

}



static void rbd_dev_update_parent(struct rbd_device *rbd_dev,

				  struct parent_image_info *pii)

{

	if (pii->pool_id == CEPH_NOPOOL || !pii->has_overlap) {

		/*

		 * Either the parent never existed, or we have

		 * record of it but the image got flattened so it no

		 * longer has a parent.  When the parent of a

		 * layered image disappears we immediately set the

		 * overlap to 0.  The effect of this is that all new

		 * requests will be treated as if the image had no

		 * parent.

		 *

		 * If !pii.has_overlap, the parent image spec is not

		 * applicable.  It's there to avoid duplication in each

		 * snapshot record.

		 */

		if (rbd_dev->parent_overlap) {

			rbd_dev->parent_overlap = 0;

			rbd_dev_parent_put(rbd_dev);

			pr_info("%s: clone has been flattened\n",

				rbd_dev->disk->disk_name);

		}

	} else {

		rbd_assert(rbd_dev->parent_spec);



		/*

		 * Update the parent overlap.  If it became zero, issue

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

		 */

		if (!pii->overlap && rbd_dev->parent_overlap)

			rbd_warn(rbd_dev,

				 "clone has become standalone (overlap 0)");

		rbd_dev->parent_overlap = pii->overlap;

	}

}



static int rbd_dev_refresh(struct rbd_device *rbd_dev)

{

	struct rbd_image_header	header = { 0 };

	struct parent_image_info pii = { 0 };

	u64 mapping_size;

	int ret;
@@ -7059,12 +7074,14 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev) 
	 * mapped image getting flattened.

	 */

	if (rbd_dev->parent) {

		ret = rbd_dev_v2_parent_info(rbd_dev);

		ret = rbd_dev_v2_parent_info(rbd_dev, &pii);

		if (ret)

			goto out;

	}



	rbd_dev_update_header(rbd_dev, &header);

	if (rbd_dev->parent)

		rbd_dev_update_parent(rbd_dev, &pii);



	if (rbd_dev->spec->snap_id == CEPH_NOSNAP) {

		rbd_dev->mapping.size = rbd_dev->header.image_size;
@@ -7078,6 +7095,7 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev) 
	if (!ret && mapping_size != rbd_dev->mapping.size)

		rbd_dev_update_size(rbd_dev);



	rbd_parent_info_cleanup(&pii);

	rbd_image_header_cleanup(&header);

	return ret;

}