Commit f785cc1d authored by Alex Elder's avatar Alex Elder
Browse files

rbd: kill incore snap_names_len 



The only thing the on-disk snap_names_len field is needed is to
size the buffer allocated to hold a copy of the snapshot names
for an rbd image.

So don't bother saving it in the in-core rbd_image_header structure.
Just use a local variable to hold the required buffer size while
it's needed.

Move the code that actually copies the snapshot names up closer
to where the required length is saved.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarYehuda Sadeh <yehuda@inktank.com>
parent 58c17b0e

drivers/block/rbd.c

+13 −13
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ struct rbd_image_header { 
	__u8 crypt_type;

	__u8 comp_type;

	struct ceph_snap_context *snapc;

	u64 snap_names_len;

	u32 total_snaps;



	char *snap_names;
@@ -534,12 +533,21 @@ static int rbd_header_from_disk(struct rbd_image_header *header, 
	header->object_prefix[len] = '\0';



	if (snap_count) {

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

		BUG_ON(header->snap_names_len > (u64) SIZE_MAX);

		header->snap_names = kmalloc(header->snap_names_len,

					     GFP_KERNEL);

		u64 snap_names_len = le64_to_cpu(ondisk->snap_names_len);



		if (snap_names_len > (u64) SIZE_MAX)

			return -EIO;

		header->snap_names = kmalloc(snap_names_len, GFP_KERNEL);

		if (!header->snap_names)

			goto out_err;

		/*

		 * Note that rbd_dev_v1_header_read() guarantees

		 * the ondisk buffer we're working with has

		 * snap_names_len bytes beyond the end of the

		 * snapshot id array, this memcpy() is safe.

		 */

		memcpy(header->snap_names, &ondisk->snaps[snap_count],

			snap_names_len);



		size = snap_count * sizeof (*header->snap_sizes);

		header->snap_sizes = kmalloc(size, GFP_KERNEL);
@@ -547,7 +555,6 @@ static int rbd_header_from_disk(struct rbd_image_header *header, 
			goto out_err;

	} else {

		WARN_ON(ondisk->snap_names_len);

		header->snap_names_len = 0;

		header->snap_names = NULL;

		header->snap_sizes = NULL;

	}
@@ -579,10 +586,6 @@ static int rbd_header_from_disk(struct rbd_image_header *header, 
			header->snap_sizes[i] =

				le64_to_cpu(ondisk->snaps[i].image_size);

		}



		/* copy snapshot names */

		memcpy(header->snap_names, &ondisk->snaps[snap_count],

			header->snap_names_len);

	}



	return 0;
@@ -592,7 +595,6 @@ out_err: 
	header->snap_sizes = NULL;

	kfree(header->snap_names);

	header->snap_names = NULL;

	header->snap_names_len = 0;

	kfree(header->object_prefix);

	header->object_prefix = NULL;
@@ -660,7 +662,6 @@ static void rbd_header_free(struct rbd_image_header *header) 
	header->snap_sizes = NULL;

	kfree(header->snap_names);

	header->snap_names = NULL;

	header->snap_names_len = 0;

	ceph_put_snap_context(header->snapc);

	header->snapc = NULL;

}
@@ -1800,7 +1801,6 @@ static int __rbd_refresh_header(struct rbd_device *rbd_dev, u64 *hver) 
	rbd_dev->header.total_snaps = h.total_snaps;

	rbd_dev->header.snapc = h.snapc;

	rbd_dev->header.snap_names = h.snap_names;

	rbd_dev->header.snap_names_len = h.snap_names_len;

	rbd_dev->header.snap_sizes = h.snap_sizes;

	/* Free the extra copy of the object prefix */

	WARN_ON(strcmp(rbd_dev->header.object_prefix, h.object_prefix));

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