On 10/31/2012 08:49 PM, Josh Durgin wrote:
> I know you've got a queue of these already, but here's another:
> rbd_dev_probe_update_spec() could definitely use some warnings
> to distinguish its error cases.
>
> Reviewed-by: Josh Durgin <josh.durgin@xxxxxxxxxxx>
Finally! I was going to accuse you of slacking for
having no comments on all of the other reviews up
to this one...
I've got some of these implemented already, I'll finish
off this as you suggest and a few other categories as
well this morning and will get them posted for review.
-Alex
>
> On 10/30/2012 06:49 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
>> @@ -70,7 +70,10 @@
>>
>> #define RBD_SNAP_HEAD_NAME "-"
>>
>> +/* 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
>> +
>> #define RBD_OBJ_PREFIX_LEN_MAX 64
>>
>> /* Feature bits */
>> @@ -658,6 +661,20 @@ out_err:
>> return -ENOMEM;
>> }
>>
>> +static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64
>> snap_id)
>> +{
>> + struct rbd_snap *snap;
>> +
>> + 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;
>> +
>> + return NULL;
>> +}
>> +
>> static int snap_by_name(struct rbd_device *rbd_dev, const char
>> *snap_name)
>> {
>>
>> @@ -2499,6 +2516,7 @@ static int rbd_dev_v2_parent_info(struct
>> rbd_device *rbd_dev)
>> goto out_err;
>> }
>> parent_spec->image_id = image_id;
>> + parent_spec->image_id_len = len;
>> ceph_decode_64_safe(&p, end, parent_spec->snap_id, out_err);
>> ceph_decode_64_safe(&p, end, overlap, out_err);
>>
>> @@ -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);
>> + 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;
>> +}
>> +
>> +/*
>> + * When a parent image gets probed, we only have the pool, image,
>> + * and snapshot ids but not the names of any of them. This call
>> + * is made later to fill in those names. It has to be done after
>> + * rbd_dev_snaps_update() has completed because some of the
>> + * information (in particular, snapshot name) is not available
>> + * until then.
>> + */
>> +static int rbd_dev_probe_update_spec(struct rbd_device *rbd_dev)
>> +{
>> + struct ceph_osd_client *osdc;
>> + const char *name;
>> + void *reply_buf = NULL;
>> + int ret;
>> +
>> + if (rbd_dev->spec->pool_name)
>> + return 0; /* Already have the names */
>> +
>> + /* Look up the pool name */
>> +
>> + osdc = &rbd_dev->rbd_client->client->osdc;
>> + name = ceph_pg_pool_name_by_id(osdc->osdmap,
>> rbd_dev->spec->pool_id);
>> + if (!name)
>> + return -EIO; /* pool id too large (>= 2^31) */
>> +
>> + rbd_dev->spec->pool_name = kstrdup(name, GFP_KERNEL);
>> + if (!rbd_dev->spec->pool_name)
>> + return -ENOMEM;
>> +
>> + /* Fetch the image name; tolerate failure here */
>> +
>> + name = rbd_dev_image_name(rbd_dev);
>> + if (name) {
>> + rbd_dev->spec->image_name_len = strlen(name);
>> + rbd_dev->spec->image_name = (char *) name;
>> + } else {
>> + pr_warning(RBD_DRV_NAME "%d "
>> + "unable to get image name for image id %s\n",
>> + rbd_dev->major, rbd_dev->spec->image_id);
>> + }
>> +
>> + /* Look up the snapshot name. */
>> +
>> + name = rbd_snap_name(rbd_dev, rbd_dev->spec->snap_id);
>> + if (!name) {
>> + ret = -EIO;
>> + goto out_err;
>> + }
>> + rbd_dev->spec->snap_name = kstrdup(name, GFP_KERNEL);
>> + if(!rbd_dev->spec->snap_name)
>> + goto out_err;
>> +
>> + return 0;
>> +out_err:
>> + kfree(reply_buf);
>> + kfree(rbd_dev->spec->pool_name);
>> + rbd_dev->spec->pool_name = NULL;
>> +
>> + return ret;
>> +}
>> +
>> static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev, u64
>> *ver)
>> {
>> size_t size;
>> @@ -3372,6 +3499,10 @@ static int rbd_dev_probe_finish(struct rbd_device
>> *rbd_dev)
>> if (ret)
>> return ret;
>>
>> + ret = rbd_dev_probe_update_spec(rbd_dev);
>> + if (ret)
>> + goto err_out_snaps;
>> +
>> ret = rbd_dev_set_mapping(rbd_dev);
>> if (ret)
>> goto err_out_snaps;
>>
>
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