Commit 9682fc6d authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
Browse files

rbd: look up snapshot name in names buffer 



Rather than scanning the list of snapshot structures for it, scan
the snapshot context buffer containing snapshot names in order to
determine for a format 1 image the name associated with a given
snapshot id.

Pull out the part of rbd_dev_v1_snap_info() that does this scan into
a new function, _rbd_dev_v1_snap_name().  Have that function return
a dynamically-allocated copy of the name, and don't duplicate it in
rbd_dev_v1_snap_info().

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent dedc81ea

drivers/block/rbd.c

+30 −10
Original line number Diff line number Diff line
@@ -66,6 +66,8 @@ 


#define RBD_SNAP_HEAD_NAME	"-"



#define	BAD_SNAP_INDEX	U32_MAX		/* invalid index into snap array */



/* This allows a single page to hold an image name sent by OSD */

#define RBD_IMAGE_NAME_LEN_MAX	(PAGE_SIZE - sizeof (__le32) - 1)

#define RBD_IMAGE_ID_LEN_MAX	64
@@ -809,6 +811,33 @@ out_err: 
	return -ENOMEM;

}



static const char *_rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u32 which)

{

	const char *snap_name;



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



	/* Skip over names until we find the one we are looking for */



	snap_name = rbd_dev->header.snap_names;

	while (which--)

		snap_name += strlen(snap_name) + 1;



	return kstrdup(snap_name, GFP_KERNEL);

}



static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id)

{

	struct ceph_snap_context *snapc = rbd_dev->header.snapc;

	u32 which;



	for (which = 0; which < snapc->num_snaps; which++)

		if (snapc->snaps[which] == snap_id)

			return which;



	return BAD_SNAP_INDEX;

}



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

{

	struct rbd_snap *snap;
@@ -3421,17 +3450,8 @@ static const char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which, 
		u64 *snap_size, u64 *snap_features)

{

	const char *snap_name;

	int i;



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



	/* Skip over names until we find the one we are looking for */



	snap_name = rbd_dev->header.snap_names;

	for (i = 0; i < which; i++)

		snap_name += strlen(snap_name) + 1;



	snap_name = kstrdup(snap_name, GFP_KERNEL);

	snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);

	if (!snap_name)

		return ERR_PTR(-ENOMEM);

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