On 10/30/2012 08:49 PM, Alex Elder wrote:
> When a layered rbd image has a parent, that parent is identified
> only by its pool id, image id, and snapshot id. Images that have
> been mapped also record *names* for those three id's.
>
> Add code to look up these names for parent images so they match
> mapped images more closely. Skip doing this for an image if it
> already has its pool name defined (this will be the case for images
> mapped by the user).
>
> It is possible that an the name of a parent image can't be
> determined, even if the image id is valid. If this occurs it
> does not preclude correct operation, so don't treat this as
> an error.
>
> On the other hand, defined pools will always have both an id and a
> name. And any snapshot of an image identified as a parent for a
> clone image will exist, and will have a name (if not it indicates
> some other internal error). So treat failure to get these bits
> of information as errors.
>
> Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
> ---
> drivers/block/rbd.c | 131
> +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 131 insertions(+)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index bce1fcf..04062c1 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
. . .
> @@ -2514,6 +2532,115 @@ out_err:
> return ret;
> }
>
> +static char *rbd_dev_image_name(struct rbd_device *rbd_dev)
> +{
> + size_t image_id_size;
> + char *image_id;
> + void *p;
> + void *end;
> + size_t size;
> + void *reply_buf = NULL;
> + size_t len = 0;
> + char *image_name = NULL;
> + int ret;
> +
> + rbd_assert(!rbd_dev->spec->image_name);
> +
> + image_id_size = sizeof (__le32) + rbd_dev->spec->image_id_len;
> + image_id = kmalloc(image_id_size, GFP_KERNEL);
> + if (!image_id)
> + return NULL;
> +
> + p = image_id;
> + end = (char *) image_id + image_id_size;
> + ceph_encode_string(&p, end, rbd_dev->spec->image_id,
> + (u32) rbd_dev->spec->image_id_len);
> +
> + size = sizeof (__le32) + RBD_IMAGE_NAME_LEN_MAX;
> + reply_buf = kmalloc(size, GFP_KERNEL);
> + if (!reply_buf)
> + goto out;
> +
> + ret = rbd_req_sync_exec(rbd_dev, RBD_DIRECTORY,
> + "rbd", "dir_get_name",
> + image_id, image_id_size,
> + (char *) reply_buf, size,
> + CEPH_OSD_FLAG_READ, NULL);
> + if (ret < 0)
> + goto out;
> + p = reply_buf;
> + end = (char *) reply_buf + size;
> + image_name = ceph_extract_encoded_string(&p, end, &len, GFP_KERNEL);
The next line will need to be changed to:
if (IS_ERR(image_name))
image_name = NULL;
else
> + if (image_name)
> + dout("%s: name is %s len is %zd\n", __func__, image_name, len);
> +out:
> + kfree(reply_buf);
> + kfree(image_id);
> +
> + return image_name;
> +}
> +
. . .
--
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