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authorAlex Elder <elder@inktank.com>2012-07-10 20:30:11 -0500
committerAlex Elder <elder@inktank.com>2012-10-01 14:30:53 -0500
commit589d30e0b3e649e2660f9a67be88e235b28bc319 (patch)
tree7430a5eea84dc3378ba69a5cd563577afb98b228 /drivers/block
parent3bb59ad515527fa75cf71d997d17cea18160da74 (diff)
downloadop-kernel-dev-589d30e0b3e649e2660f9a67be88e235b28bc319.zip
op-kernel-dev-589d30e0b3e649e2660f9a67be88e235b28bc319.tar.gz
rbd: define rbd_dev_image_id()
New format 2 rbd images are permanently identified by a unique image id. Each rbd image also has a name, but the name can be changed. A format 2 rbd image will have an object--whose name is based on the image name--which maps an image's name to its image id. Create a new function rbd_dev_image_id() that checks for the existence of the image id object, and if it's found, records the image id in the rbd_device structure. Create a new rbd device attribute (/sys/bus/rbd/<num>/image_id) that makes this information available. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/rbd.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index b895613..34f46c3 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -66,6 +66,8 @@
#define RBD_SNAP_HEAD_NAME "-"
+#define RBD_IMAGE_ID_LEN_MAX 64
+
/*
* An RBD device name will be "rbd#", where the "rbd" comes from
* RBD_DRV_NAME above, and # is a unique integer identifier.
@@ -173,6 +175,8 @@ struct rbd_device {
spinlock_t lock; /* queue lock */
struct rbd_image_header header;
+ char *image_id;
+ size_t image_id_len;
char *image_name;
size_t image_name_len;
char *header_name;
@@ -1987,6 +1991,14 @@ static ssize_t rbd_name_show(struct device *dev,
return sprintf(buf, "%s\n", rbd_dev->image_name);
}
+static ssize_t rbd_image_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
+
+ return sprintf(buf, "%s\n", rbd_dev->image_id);
+}
+
static ssize_t rbd_snap_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -2015,6 +2027,7 @@ static DEVICE_ATTR(client_id, S_IRUGO, rbd_client_id_show, NULL);
static DEVICE_ATTR(pool, S_IRUGO, rbd_pool_show, NULL);
static DEVICE_ATTR(pool_id, S_IRUGO, rbd_pool_id_show, NULL);
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(create_snap, S_IWUSR, NULL, rbd_snap_add);
@@ -2026,6 +2039,7 @@ static struct attribute *rbd_attrs[] = {
&dev_attr_pool.attr,
&dev_attr_pool_id.attr,
&dev_attr_name.attr,
+ &dev_attr_image_id.attr,
&dev_attr_current_snap.attr,
&dev_attr_refresh.attr,
&dev_attr_create_snap.attr,
@@ -2553,6 +2567,75 @@ out_err:
return err_ptr;
}
+/*
+ * An rbd format 2 image has a unique identifier, distinct from the
+ * name given to it by the user. Internally, that identifier is
+ * what's used to specify the names of objects related to the image.
+ *
+ * A special "rbd id" object is used to map an rbd image name to its
+ * id. If that object doesn't exist, then there is no v2 rbd image
+ * with the supplied name.
+ *
+ * This function will record the given rbd_dev's image_id field if
+ * it can be determined, and in that case will return 0. If any
+ * errors occur a negative errno will be returned and the rbd_dev's
+ * image_id field will be unchanged (and should be NULL).
+ */
+static int rbd_dev_image_id(struct rbd_device *rbd_dev)
+{
+ int ret;
+ size_t size;
+ char *object_name;
+ void *response;
+ void *p;
+
+ /*
+ * First, see if the format 2 image id file exists, and if
+ * so, get the image's persistent id from it.
+ */
+ size = sizeof (RBD_ID_PREFIX) + rbd_dev->image_name_len;
+ object_name = kmalloc(size, GFP_NOIO);
+ if (!object_name)
+ return -ENOMEM;
+ sprintf(object_name, "%s%s", RBD_ID_PREFIX, rbd_dev->image_name);
+ dout("rbd id object name is %s\n", object_name);
+
+ /* Response will be an encoded string, which includes a length */
+
+ size = sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX;
+ response = kzalloc(size, GFP_NOIO);
+ if (!response) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = rbd_req_sync_exec(rbd_dev, object_name,
+ "rbd", "get_id",
+ NULL, 0,
+ response, RBD_IMAGE_ID_LEN_MAX,
+ CEPH_OSD_FLAG_READ, NULL);
+ dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret);
+ if (ret < 0)
+ goto out;
+
+ p = response;
+ rbd_dev->image_id = ceph_extract_encoded_string(&p,
+ p + RBD_IMAGE_ID_LEN_MAX,
+ &rbd_dev->image_id_len,
+ GFP_NOIO);
+ if (IS_ERR(rbd_dev->image_id)) {
+ ret = PTR_ERR(rbd_dev->image_id);
+ rbd_dev->image_id = NULL;
+ } else {
+ dout("image_id is %s\n", rbd_dev->image_id);
+ }
+out:
+ kfree(response);
+ kfree(object_name);
+
+ return ret;
+}
+
static ssize_t rbd_add(struct bus_type *bus,
const char *buf,
size_t count)
@@ -2600,6 +2683,21 @@ static ssize_t rbd_add(struct bus_type *bus,
goto err_out_client;
rbd_dev->pool_id = rc;
+ rc = rbd_dev_image_id(rbd_dev);
+ if (!rc) {
+ rc = -ENOTSUPP; /* Not actually supporting format 2 yet */
+ goto err_out_client;
+ }
+
+ /* Version 1 images have no id; empty string is used */
+
+ rbd_dev->image_id = kstrdup("", GFP_KERNEL);
+ if (!rbd_dev->image_id) {
+ rc = -ENOMEM;
+ goto err_out_client;
+ }
+ rbd_dev->image_id_len = 0;
+
/* Create the name of the header object */
rbd_dev->header_name = kmalloc(rbd_dev->image_name_len
@@ -2691,6 +2789,7 @@ err_out_header:
err_out_client:
kfree(rbd_dev->header_name);
rbd_put_client(rbd_dev);
+ kfree(rbd_dev->image_id);
err_out_args:
kfree(rbd_dev->mapping.snap_name);
kfree(rbd_dev->image_name);
@@ -2746,6 +2845,7 @@ static void rbd_dev_release(struct device *dev)
/* done with the id, and with the rbd_dev */
kfree(rbd_dev->mapping.snap_name);
+ kfree(rbd_dev->image_id);
kfree(rbd_dev->header_name);
kfree(rbd_dev->pool_name);
kfree(rbd_dev->image_name);
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