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Commit 54cac61f authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
Browse files

rbd: use snap_id not index to look up snap info 



In order to align with what was needed for format 1 rbd images,
rbd_dev_v2_snap_info() was set up to take as argument an index into
the array of snapshot ids in a rbd device's snapshot context.

This switches that around, so we pass the snapshot id instead.
In doing this, rbd_snap_name() now returns a dynamically-allocated
string rather than a fixed one, so there's no need to make a
duplicate in its caller, rbd_dev_spec_update().

This means the following functions take a snapshot id where they
previously used an index value:
    rbd_dev_snap_info()
    rbd_dev_v1_snap_info()
    rbd_dev_v2_snap_info()

A new function, rbd_dev_snap_index(), determines the snap index for
format 1 images and uses it to look up the name.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 9682fc6d

drivers/block/rbd.c

+37 −31
Original line number Diff line number Diff line
@@ -433,6 +433,8 @@ static void rbd_dev_remove_parent(struct rbd_device *rbd_dev); 


static int rbd_dev_refresh(struct rbd_device *rbd_dev);

static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev);

static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,

					u64 snap_id);



static int rbd_open(struct block_device *bdev, fmode_t mode)

{
@@ -838,18 +840,27 @@ static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id) 
	return BAD_SNAP_INDEX;

}



static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id)

static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u64 snap_id)

{

	struct rbd_snap *snap;

	u32 which;



	which = rbd_dev_snap_index(rbd_dev, snap_id);

	if (which == BAD_SNAP_INDEX)

		return NULL;



	return _rbd_dev_v1_snap_name(rbd_dev, which);

}



static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id)

{

	if (snap_id == CEPH_NOSNAP)

		return RBD_SNAP_HEAD_NAME;



	list_for_each_entry(snap, &rbd_dev->snaps, node)

		if (snap_id == snap->id)

			return snap->name;

	rbd_assert(rbd_image_format_valid(rbd_dev->image_format));

	if (rbd_dev->image_format == 1)

		return rbd_dev_v1_snap_name(rbd_dev, snap_id);



	return NULL;

	return rbd_dev_v2_snap_name(rbd_dev, snap_id);

}



static struct rbd_snap *snap_by_name(struct rbd_device *rbd_dev,
@@ -3446,11 +3457,15 @@ static struct rbd_snap *rbd_snap_create(struct rbd_device *rbd_dev, 
 * Returns a dynamically-allocated snapshot name if successful, or a

 * pointer-coded error otherwise.

 */

static const char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which,

		u64 *snap_size, u64 *snap_features)

static const char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev,

			u64 snap_id, u64 *snap_size, u64 *snap_features)

{

	const char *snap_name;

	u32 which;



	which = rbd_dev_snap_index(rbd_dev, snap_id);

	if (which == BAD_SNAP_INDEX)

		return ERR_PTR(-ENOENT);

	snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);

	if (!snap_name)

		return ERR_PTR(-ENOMEM);
@@ -3815,12 +3830,6 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev) 
	/* Look up the snapshot name, and make a copy */



	snap_name = rbd_snap_name(rbd_dev, spec->snap_id);

	if (!snap_name) {

		rbd_warn(rbd_dev, "no snapshot with id %llu", spec->snap_id);

		ret = -EIO;

		goto out_err;

	}

	snap_name = kstrdup(snap_name, GFP_KERNEL);

	if (!snap_name) {

		ret = -ENOMEM;

		goto out_err;
@@ -3909,11 +3918,12 @@ out: 
	return ret;

}



static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev, u32 which)

static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,

					u64 snap_id)

{

	size_t size;

	void *reply_buf;

	__le64 snap_id;

	__le64 snapid;

	int ret;

	void *p;

	void *end;
@@ -3924,11 +3934,10 @@ static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev, u32 which) 
	if (!reply_buf)

		return ERR_PTR(-ENOMEM);



	rbd_assert(which < rbd_dev->header.snapc->num_snaps);

	snap_id = cpu_to_le64(rbd_dev->header.snapc->snaps[which]);

	snapid = cpu_to_le64(snap_id);

	ret = rbd_obj_method_sync(rbd_dev, rbd_dev->header_name,

				"rbd", "get_snapshot_name",

				&snap_id, sizeof (snap_id),

				&snapid, sizeof (snapid),

				reply_buf, size);

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

	if (ret < 0) {
@@ -3943,24 +3952,21 @@ static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev, u32 which) 
		goto out;



	dout("  snap_id 0x%016llx snap_name = %s\n",

		(unsigned long long)le64_to_cpu(snap_id), snap_name);

		(unsigned long long)snap_id, snap_name);

out:

	kfree(reply_buf);



	return snap_name;

}



static const char *rbd_dev_v2_snap_info(struct rbd_device *rbd_dev, u32 which,

		u64 *snap_size, u64 *snap_features)

static const char *rbd_dev_v2_snap_info(struct rbd_device *rbd_dev,

			u64 snap_id, u64 *snap_size, u64 *snap_features)

{

	u64 snap_id;

	u64 size;

	u64 features;

	const char *snap_name;

	int ret;



	rbd_assert(which < rbd_dev->header.snapc->num_snaps);

	snap_id = rbd_dev->header.snapc->snaps[which];

	ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, &size);

	if (ret)

		goto out_err;
@@ -3969,7 +3975,7 @@ static const char *rbd_dev_v2_snap_info(struct rbd_device *rbd_dev, u32 which, 
	if (ret)

		goto out_err;



	snap_name = rbd_dev_v2_snap_name(rbd_dev, which);

	snap_name = rbd_dev_v2_snap_name(rbd_dev, snap_id);

	if (!IS_ERR(snap_name)) {

		*snap_size = size;

		*snap_features = features;
@@ -3980,14 +3986,14 @@ out_err: 
	return ERR_PTR(ret);

}



static const char *rbd_dev_snap_info(struct rbd_device *rbd_dev, u32 which,

		u64 *snap_size, u64 *snap_features)

static const char *rbd_dev_snap_info(struct rbd_device *rbd_dev,

		u64 snap_id, u64 *snap_size, u64 *snap_features)

{

	if (rbd_dev->image_format == 1)

		return rbd_dev_v1_snap_info(rbd_dev, which,

		return rbd_dev_v1_snap_info(rbd_dev, snap_id,

					snap_size, snap_features);

	if (rbd_dev->image_format == 2)

		return rbd_dev_v2_snap_info(rbd_dev, which,

		return rbd_dev_v2_snap_info(rbd_dev, snap_id,

					snap_size, snap_features);

	return ERR_PTR(-EINVAL);

}
@@ -4085,7 +4091,7 @@ static int rbd_dev_snaps_update(struct rbd_device *rbd_dev) 
			continue;

		}



		snap_name = rbd_dev_snap_info(rbd_dev, index,

		snap_name = rbd_dev_snap_info(rbd_dev, snap_id,

					&snap_size, &snap_features);

		if (IS_ERR(snap_name)) {

			ret = PTR_ERR(snap_name);