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Commit f84344f3 authored by Alex Elder's avatar Alex Elder
Browse files

rbd: separate mapping info in rbd_dev 



Several fields in a struct rbd_dev are related to what is mapped, as
opposed to the actual base rbd image.  If the base image is mapped
these are almost unneeded, but if a snapshot is mapped they describe
information about that snapshot.

In some contexts this can be a little bit confusing.  So group these
mapping-related field into a structure to make it clear what they
are describing.

This also includes a minor change that rearranges the fields in the
in-core image header structure so that invariant fields are at the
top, followed by those that change.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent c9aadfe7

drivers/block/rbd.c

+45 −38
Original line number Diff line number Diff line
@@ -81,13 +81,15 @@ 
 * block device image metadata (in-memory version)

 */

struct rbd_image_header {

	u64 image_size;

	/* These four fields never change for a given rbd image */

	char *object_prefix;

	__u8 obj_order;

	__u8 crypt_type;

	__u8 comp_type;

	struct ceph_snap_context *snapc;



	/* The remaining fields need to be updated occasionally */

	u64 image_size;

	struct ceph_snap_context *snapc;

	char *snap_names;

	u64 *snap_sizes;
@@ -146,6 +148,13 @@ struct rbd_snap { 
	u64			id;

};



struct rbd_mapping {

	char                    *snap_name;

	u64                     snap_id;

	bool                    snap_exists;

	bool			read_only;

};



/*

 * a single device

 */
@@ -174,13 +183,8 @@ struct rbd_device { 


	/* protects updating the header */

	struct rw_semaphore     header_rwsem;

	/* name of the snapshot this device reads from */

	char                    *snap_name;

	/* id of the snapshot this device reads from */

	u64                     snap_id;	/* current snapshot id */

	/* whether the snap_id this device reads from still exists */

	bool                    snap_exists;

	bool			read_only;



	struct rbd_mapping	mapping;



	struct list_head	node;
@@ -261,11 +265,11 @@ static int rbd_open(struct block_device *bdev, fmode_t mode) 
{

	struct rbd_device *rbd_dev = bdev->bd_disk->private_data;



	if ((mode & FMODE_WRITE) && rbd_dev->read_only)

	if ((mode & FMODE_WRITE) && rbd_dev->mapping.read_only)

		return -EROFS;



	rbd_get_dev(rbd_dev);

	set_device_ro(bdev, rbd_dev->read_only);

	set_device_ro(bdev, rbd_dev->mapping.read_only);



	return 0;

}
@@ -375,7 +379,7 @@ enum { 
static match_table_t rbd_opts_tokens = {

	/* int args above */

	/* string args above */

	{Opt_read_only, "read_only"},

	{Opt_read_only, "mapping.read_only"},

	{Opt_read_only, "ro"},		/* Alternate spelling */

	{Opt_read_write, "read_write"},

	{Opt_read_write, "rw"},		/* Alternate spelling */
@@ -583,13 +587,13 @@ static int rbd_header_from_disk(struct rbd_image_header *header, 
		header->snap_sizes = NULL;

	}



	header->image_size = le64_to_cpu(ondisk->image_size);

	header->obj_order = ondisk->options.order;

	header->crypt_type = ondisk->options.crypt_type;

	header->comp_type = ondisk->options.comp_type;



	/* Allocate and fill in the snapshot context */



	header->image_size = le64_to_cpu(ondisk->image_size);

	size = sizeof (struct ceph_snap_context);

	size += snap_count * sizeof (header->snapc->snaps[0]);

	header->snapc = kzalloc(size, GFP_KERNEL);
@@ -645,23 +649,24 @@ static int rbd_header_set_snap(struct rbd_device *rbd_dev, u64 *size) 


	down_write(&rbd_dev->header_rwsem);



	if (!memcmp(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,

	if (!memcmp(rbd_dev->mapping.snap_name, RBD_SNAP_HEAD_NAME,

		    sizeof (RBD_SNAP_HEAD_NAME))) {

		rbd_dev->snap_id = CEPH_NOSNAP;

		rbd_dev->snap_exists = false;

		rbd_dev->read_only = rbd_dev->rbd_opts.read_only;

		rbd_dev->mapping.snap_id = CEPH_NOSNAP;

		rbd_dev->mapping.snap_exists = false;

		rbd_dev->mapping.read_only = rbd_dev->rbd_opts.read_only;

		if (size)

			*size = rbd_dev->header.image_size;

	} else {

		u64 snap_id = 0;



		ret = snap_by_name(&rbd_dev->header, rbd_dev->snap_name,

		ret = snap_by_name(&rbd_dev->header,

					rbd_dev->mapping.snap_name,

					&snap_id, size);

		if (ret < 0)

			goto done;

		rbd_dev->snap_id = snap_id;

		rbd_dev->snap_exists = true;

		rbd_dev->read_only = true;	/* No choice for snapshots */

		rbd_dev->mapping.snap_id = snap_id;

		rbd_dev->mapping.snap_exists = true;

		rbd_dev->mapping.read_only = true;

	}



	ret = 0;
@@ -1532,7 +1537,7 @@ static void rbd_rq_fn(struct request_queue *q) 
		size = blk_rq_bytes(rq);

		ofs = blk_rq_pos(rq) * SECTOR_SIZE;

		rq_bio = rq->bio;

		if (do_write && rbd_dev->read_only) {

		if (do_write && rbd_dev->mapping.read_only) {

			__blk_end_request_all(rq, -EROFS);

			continue;

		}
@@ -1541,7 +1546,8 @@ static void rbd_rq_fn(struct request_queue *q) 


		down_read(&rbd_dev->header_rwsem);



		if (rbd_dev->snap_id != CEPH_NOSNAP && !rbd_dev->snap_exists) {

		if (rbd_dev->mapping.snap_id != CEPH_NOSNAP &&

				!rbd_dev->mapping.snap_exists) {

			up_read(&rbd_dev->header_rwsem);

			dout("request for non-existent snapshot");

			spin_lock_irq(q->queue_lock);
@@ -1595,7 +1601,7 @@ static void rbd_rq_fn(struct request_queue *q) 
					      coll, cur_seg);

			else

				rbd_req_read(rq, rbd_dev,

					     rbd_dev->snap_id,

					     rbd_dev->mapping.snap_id,

					     ofs,

					     op_size, bio,

					     coll, cur_seg);
@@ -1767,7 +1773,7 @@ static int rbd_header_add_snap(struct rbd_device *rbd_dev, 
	struct ceph_mon_client *monc;



	/* we should create a snapshot only if we're pointing at the head */

	if (rbd_dev->snap_id != CEPH_NOSNAP)

	if (rbd_dev->mapping.snap_id != CEPH_NOSNAP)

		return -EINVAL;



	monc = &rbd_dev->rbd_client->client->monc;
@@ -1821,7 +1827,7 @@ static int __rbd_refresh_header(struct rbd_device *rbd_dev, u64 *hver) 
	down_write(&rbd_dev->header_rwsem);



	/* resized? */

	if (rbd_dev->snap_id == CEPH_NOSNAP) {

	if (rbd_dev->mapping.snap_id == CEPH_NOSNAP) {

		sector_t size = (sector_t) h.image_size / SECTOR_SIZE;



		dout("setting size to %llu sectors", (unsigned long long) size);
@@ -2004,7 +2010,7 @@ static ssize_t rbd_snap_show(struct device *dev, 
{

	struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);



	return sprintf(buf, "%s\n", rbd_dev->snap_name);

	return sprintf(buf, "%s\n", rbd_dev->mapping.snap_name);

}



static ssize_t rbd_image_refresh(struct device *dev,
@@ -2205,11 +2211,12 @@ static int rbd_dev_snap_devs_update(struct rbd_device *rbd_dev) 


			/* Existing snapshot not in the new snap context */



			if (rbd_dev->snap_id == snap->id)

				rbd_dev->snap_exists = false;

			if (rbd_dev->mapping.snap_id == snap->id)

				rbd_dev->mapping.snap_exists = false;

			__rbd_remove_snap_dev(snap);

			dout("%ssnap id %llu has been removed\n",

				rbd_dev->snap_id == snap->id ? "mapped " : "",

				rbd_dev->mapping.snap_id == snap->id ?

								"mapped " : "",

				(unsigned long long) snap->id);



			/* Done with this list entry; advance */
@@ -2522,18 +2529,18 @@ static int rbd_add_parse_args(struct rbd_device *rbd_dev, 
	 * The snapshot name is optional.  If none is is supplied,

	 * we use the default value.

	 */

	rbd_dev->snap_name = dup_token(&buf, &len);

	if (!rbd_dev->snap_name)

	rbd_dev->mapping.snap_name = dup_token(&buf, &len);

	if (!rbd_dev->mapping.snap_name)

		goto out_err;

	if (!len) {

		/* Replace the empty name with the default */

		kfree(rbd_dev->snap_name);

		rbd_dev->snap_name

		kfree(rbd_dev->mapping.snap_name);

		rbd_dev->mapping.snap_name

			= kmalloc(sizeof (RBD_SNAP_HEAD_NAME), GFP_KERNEL);

		if (!rbd_dev->snap_name)

		if (!rbd_dev->mapping.snap_name)

			goto out_err;



		memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,

		memcpy(rbd_dev->mapping.snap_name, RBD_SNAP_HEAD_NAME,

			sizeof (RBD_SNAP_HEAD_NAME));

	}
@@ -2642,7 +2649,7 @@ static ssize_t rbd_add(struct bus_type *bus, 
	rbd_put_client(rbd_dev);

err_put_id:

	if (rbd_dev->pool_name) {

		kfree(rbd_dev->snap_name);

		kfree(rbd_dev->mapping.snap_name);

		kfree(rbd_dev->header_name);

		kfree(rbd_dev->image_name);

		kfree(rbd_dev->pool_name);
@@ -2695,7 +2702,7 @@ static void rbd_dev_release(struct device *dev) 
	unregister_blkdev(rbd_dev->major, rbd_dev->name);



	/* done with the id, and with the rbd_dev */

	kfree(rbd_dev->snap_name);

	kfree(rbd_dev->mapping.snap_name);

	kfree(rbd_dev->header_name);

	kfree(rbd_dev->pool_name);

	kfree(rbd_dev->image_name);