| Message ID | 504A3AB7.2020600@inktank.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/07/2012 11:19 AM, Alex Elder wrote: > 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> > --- > Documentation/ABI/testing/sysfs-bus-rbd | 5 ++ > drivers/block/rbd.c | 99 > +++++++++++++++++++++++++++++++ > 2 files changed, 104 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-bus-rbd > b/Documentation/ABI/testing/sysfs-bus-rbd > index 3c17b62..7cbbe34 100644 > --- a/Documentation/ABI/testing/sysfs-bus-rbd > +++ b/Documentation/ABI/testing/sysfs-bus-rbd > @@ -33,6 +33,11 @@ name > > The name of the rbd image. > > +image_id > + > + The unique id for the rbd image. (For rbd image format 1 > + this is empty.) > + > pool > > The name of the storage pool where this rbd image resides. > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index ba68566..5a3132e 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, > @@ -2548,6 +2562,75 @@ 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; > + ret = 0; /* rbd_req_sync_exec() can return positive */ The get_id class method will not return positive. > + > + 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; It would be clearer that this can't stay NULL if it were initialized here instead of in the caller. > + } else > + dout("image_id is %s\n", rbd_dev->image_id); If the first branch got braces, the second one should too. > +out: > + kfree(response); > + kfree(object_name); > + > + return ret; > +} > + > static ssize_t rbd_add(struct bus_type *bus, > const char *buf, > size_t count) > @@ -2597,6 +2680,20 @@ 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 == -ENOENT) { It's more than just -ENOENT. If the osd doesn't have a get_id method for example, it will be -EINVAL. It's probably best to try format 1 if any error occurred, rather than trying to come up with an exhaustive list that won't change in the future. > + /* 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; > + } else { > + /* Not actually supporting format 2 yet */ > + goto err_out_client; > + } > + > /* Create the name of the header object */ > > rbd_dev->header_name = kmalloc(rbd_dev->image_name_len > @@ -2688,6 +2785,7 @@ 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); > @@ -2744,6 +2842,7 @@ 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); > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/ABI/testing/sysfs-bus-rbd b/Documentation/ABI/testing/sysfs-bus-rbd index 3c17b62..7cbbe34 100644 --- a/Documentation/ABI/testing/sysfs-bus-rbd +++ b/Documentation/ABI/testing/sysfs-bus-rbd @@ -33,6 +33,11 @@ name The name of the rbd image. +image_id + + The unique id for the rbd image. (For rbd image format 1 + this is empty.) + pool The name of the storage pool where this rbd image resides. diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index ba68566..5a3132e 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);
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> --- Documentation/ABI/testing/sysfs-bus-rbd | 5 ++ drivers/block/rbd.c | 99 +++++++++++++++++++++++++++++++ 2 files changed, 104 insertions(+) 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, @@ -2548,6 +2562,75 @@ 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; + ret = 0; /* rbd_req_sync_exec() can return positive */ + + 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) @@ -2597,6 +2680,20 @@ 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 == -ENOENT) { + /* 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; + } else { + /* Not actually supporting format 2 yet */ + goto err_out_client; + } + /* Create the name of the header object */ rbd_dev->header_name = kmalloc(rbd_dev->image_name_len @@ -2688,6 +2785,7 @@ 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); @@ -2744,6 +2842,7 @@ 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);