Commit 86b00e0d authored by Alex Elder's avatar Alex Elder

rbd: get parent spec for version 2 images

Add support for getting the the information identifying the parent
image for rbd images that have them.  The child image holds a
reference to its parent image specification structure.  Create a new
entry "parent" in /sys/bus/rbd/image/N/ to report the identifying
information for the parent image, if any.
Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent a92ffdf8
......@@ -70,6 +70,10 @@ snap_*
A directory per each snapshot
parent
Information identifying the pool, image, and snapshot id for
the parent image in a layered rbd image (format 2 only).
Entries under /sys/bus/rbd/devices/<dev-id>/snap_<snap-name>
-------------------------------------------------------------
......
......@@ -217,6 +217,9 @@ struct rbd_device {
struct ceph_osd_event *watch_event;
struct ceph_osd_request *watch_request;
struct rbd_spec *parent_spec;
u64 parent_overlap;
/* protects updating the header */
struct rw_semaphore header_rwsem;
......@@ -2009,6 +2012,49 @@ static ssize_t rbd_snap_show(struct device *dev,
return sprintf(buf, "%s\n", rbd_dev->spec->snap_name);
}
/*
* For an rbd v2 image, shows the pool id, image id, and snapshot id
* for the parent image. If there is no parent, simply shows
* "(no parent image)".
*/
static ssize_t rbd_parent_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
struct rbd_spec *spec = rbd_dev->parent_spec;
int count;
char *bufp = buf;
if (!spec)
return sprintf(buf, "(no parent image)\n");
count = sprintf(bufp, "pool_id %llu\npool_name %s\n",
(unsigned long long) spec->pool_id, spec->pool_name);
if (count < 0)
return count;
bufp += count;
count = sprintf(bufp, "image_id %s\nimage_name %s\n", spec->image_id,
spec->image_name ? spec->image_name : "(unknown)");
if (count < 0)
return count;
bufp += count;
count = sprintf(bufp, "snap_id %llu\nsnap_name %s\n",
(unsigned long long) spec->snap_id, spec->snap_name);
if (count < 0)
return count;
bufp += count;
count = sprintf(bufp, "overlap %llu\n", rbd_dev->parent_overlap);
if (count < 0)
return count;
bufp += count;
return (ssize_t) (bufp - buf);
}
static ssize_t rbd_image_refresh(struct device *dev,
struct device_attribute *attr,
const char *buf,
......@@ -2032,6 +2078,7 @@ static DEVICE_ATTR(name, S_IRUGO, rbd_name_show, NULL);
static DEVICE_ATTR(image_id, S_IRUGO, rbd_image_id_show, NULL);
static DEVICE_ATTR(refresh, S_IWUSR, NULL, rbd_image_refresh);
static DEVICE_ATTR(current_snap, S_IRUGO, rbd_snap_show, NULL);
static DEVICE_ATTR(parent, S_IRUGO, rbd_parent_show, NULL);
static struct attribute *rbd_attrs[] = {
&dev_attr_size.attr,
......@@ -2043,6 +2090,7 @@ static struct attribute *rbd_attrs[] = {
&dev_attr_name.attr,
&dev_attr_image_id.attr,
&dev_attr_current_snap.attr,
&dev_attr_parent.attr,
&dev_attr_refresh.attr,
NULL
};
......@@ -2192,6 +2240,7 @@ struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
static void rbd_dev_destroy(struct rbd_device *rbd_dev)
{
rbd_spec_put(rbd_dev->parent_spec);
kfree(rbd_dev->header_name);
rbd_put_client(rbd_dev->rbd_client);
rbd_spec_put(rbd_dev->spec);
......@@ -2400,6 +2449,71 @@ static int rbd_dev_v2_features(struct rbd_device *rbd_dev)
&rbd_dev->header.features);
}
static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
{
struct rbd_spec *parent_spec;
size_t size;
void *reply_buf = NULL;
__le64 snapid;
void *p;
void *end;
char *image_id;
u64 overlap;
size_t len = 0;
int ret;
parent_spec = rbd_spec_alloc();
if (!parent_spec)
return -ENOMEM;
size = sizeof (__le64) + /* pool_id */
sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX + /* image_id */
sizeof (__le64) + /* snap_id */
sizeof (__le64); /* overlap */
reply_buf = kmalloc(size, GFP_KERNEL);
if (!reply_buf) {
ret = -ENOMEM;
goto out_err;
}
snapid = cpu_to_le64(CEPH_NOSNAP);
ret = rbd_req_sync_exec(rbd_dev, rbd_dev->header_name,
"rbd", "get_parent",
(char *) &snapid, sizeof (snapid),
(char *) reply_buf, size,
CEPH_OSD_FLAG_READ, NULL);
dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret);
if (ret < 0)
goto out_err;
ret = -ERANGE;
p = reply_buf;
end = (char *) reply_buf + size;
ceph_decode_64_safe(&p, end, parent_spec->pool_id, out_err);
if (parent_spec->pool_id == CEPH_NOPOOL)
goto out; /* No parent? No problem. */
image_id = ceph_extract_encoded_string(&p, end, &len, GFP_KERNEL);
if (IS_ERR(image_id)) {
ret = PTR_ERR(image_id);
goto out_err;
}
parent_spec->image_id = image_id;
ceph_decode_64_safe(&p, end, parent_spec->snap_id, out_err);
ceph_decode_64_safe(&p, end, overlap, out_err);
rbd_dev->parent_overlap = overlap;
rbd_dev->parent_spec = parent_spec;
parent_spec = NULL; /* rbd_dev now owns this */
out:
ret = 0;
out_err:
kfree(reply_buf);
rbd_spec_put(parent_spec);
return ret;
}
static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev, u64 *ver)
{
size_t size;
......@@ -3154,6 +3268,12 @@ static int rbd_dev_v1_probe(struct rbd_device *rbd_dev)
ret = rbd_read_header(rbd_dev, &rbd_dev->header);
if (ret < 0)
goto out_err;
/* Version 1 images have no parent (no layering) */
rbd_dev->parent_spec = NULL;
rbd_dev->parent_overlap = 0;
rbd_dev->image_format = 1;
dout("discovered version 1 image, header name is %s\n",
......@@ -3205,6 +3325,14 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)
if (ret < 0)
goto out_err;
/* If the image supports layering, get the parent info */
if (rbd_dev->header.features & RBD_FEATURE_LAYERING) {
ret = rbd_dev_v2_parent_info(rbd_dev);
if (ret < 0)
goto out_err;
}
/* crypto and compression type aren't (yet) supported for v2 images */
rbd_dev->header.crypt_type = 0;
......@@ -3224,6 +3352,9 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)
return 0;
out_err:
rbd_dev->parent_overlap = 0;
rbd_spec_put(rbd_dev->parent_spec);
rbd_dev->parent_spec = NULL;
kfree(rbd_dev->header_name);
rbd_dev->header_name = NULL;
kfree(rbd_dev->header.object_prefix);
......
......@@ -87,6 +87,8 @@ struct ceph_pg {
*
* lpgp_num -- as above.
*/
#define CEPH_NOPOOL ((__u64) (-1)) /* pool id not defined */
#define CEPH_PG_TYPE_REP 1
#define CEPH_PG_TYPE_RAID4 2
#define CEPH_PG_POOL_VERSION 2
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment