On 07/24/2014 03:42 AM, Ilya Dryomov wrote:
> rbd_dev_spec_update() has two modes of operation, with nothing in
> common between them. Split it into two functions, one for each mode
> and make our expectations more clear.
>
> Signed-off-by: Ilya Dryomov <ilya.dryomov@xxxxxxxxxxx>
Looks good.
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
> ---
> drivers/block/rbd.c | 79 +++++++++++++++++++++++++++++++--------------------
> 1 file changed, 48 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 4541f6027e4a..23df1773ef77 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -3798,6 +3798,9 @@ static struct rbd_spec *rbd_spec_alloc(void)
> spec = kzalloc(sizeof (*spec), GFP_KERNEL);
> if (!spec)
> return NULL;
> +
> + spec->pool_id = CEPH_NOPOOL;
> + spec->snap_id = CEPH_NOSNAP;
> kref_init(&spec->kref);
>
> return spec;
> @@ -4257,18 +4260,38 @@ static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
> }
>
> /*
> - * When an rbd image has a parent image, it is identified by the
> - * pool, image, and snapshot ids (not names). This function fills
> - * in the names for those ids. (It's OK if we can't figure out the
> - * name for an image id, but the pool and snapshot ids should always
> - * exist and have names.) All names in an rbd spec are dynamically
> - * allocated.
> + * An image being mapped will have everything but the snap id.
> + */
> +static int rbd_spec_fill_snap_id(struct rbd_device *rbd_dev)
> +{
> + struct rbd_spec *spec = rbd_dev->spec;
> +
> + rbd_assert(spec->pool_id != CEPH_NOPOOL && spec->pool_name);
> + rbd_assert(spec->image_id && spec->image_name);
> + rbd_assert(spec->snap_name);
> +
> + if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
> + u64 snap_id;
> +
> + snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
> + if (snap_id == CEPH_NOSNAP)
> + return -ENOENT;
> +
> + spec->snap_id = snap_id;
> + } else {
> + spec->snap_id = CEPH_NOSNAP;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * A parent image will have all ids but none of the names.
> *
> - * When an image being mapped (not a parent) is probed, we have the
> - * pool name and pool id, image name and image id, and the snapshot
> - * name. The only thing we're missing is the snapshot id.
> + * All names in an rbd spec are dynamically allocated. It's OK if we
> + * can't figure out the name for an image id.
> */
> -static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
> +static int rbd_spec_fill_names(struct rbd_device *rbd_dev)
> {
> struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
> struct rbd_spec *spec = rbd_dev->spec;
> @@ -4277,24 +4300,9 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
> const char *snap_name;
> int ret;
>
> - /*
> - * An image being mapped will have the pool name (etc.), but
> - * we need to look up the snapshot id.
> - */
> - if (spec->pool_name) {
> - if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
> - u64 snap_id;
> -
> - snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
> - if (snap_id == CEPH_NOSNAP)
> - return -ENOENT;
> - spec->snap_id = snap_id;
> - } else {
> - spec->snap_id = CEPH_NOSNAP;
> - }
> -
> - return 0;
> - }
> + rbd_assert(spec->pool_id != CEPH_NOPOOL);
> + rbd_assert(spec->image_id);
> + rbd_assert(spec->snap_id != CEPH_NOSNAP);
>
> /* Get the pool name; we have to make our own copy of this */
>
> @@ -4313,7 +4321,7 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
> if (!image_name)
> rbd_warn(rbd_dev, "unable to get image name");
>
> - /* Look up the snapshot name, and make a copy */
> + /* Fetch the snapshot name */
>
> snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
> if (IS_ERR(snap_name)) {
> @@ -4326,10 +4334,10 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev)
> spec->snap_name = snap_name;
>
> return 0;
> +
> out_err:
> kfree(image_name);
> kfree(pool_name);
> -
> return ret;
> }
>
> @@ -5158,7 +5166,16 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
> if (ret)
> goto err_out_watch;
>
> - ret = rbd_dev_spec_update(rbd_dev);
> + /*
> + * If this image is the one being mapped, we have pool name and
> + * id, image name and id, and snap name - need to fill snap id.
> + * Otherwise this is a parent image, identified by pool, image
> + * and snap ids - need to fill in names for those ids.
> + */
> + if (mapping)
> + ret = rbd_spec_fill_snap_id(rbd_dev);
> + else
> + ret = rbd_spec_fill_names(rbd_dev);
> if (ret)
> goto err_out_probe;
>
>
--
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