rbd: dynamically allocate snapshot name
There is no need to impose a small limit the length of the snapshot
name recorded for an rbd image in a struct rbd_dev. Remove the
limitation by allocating space for the snapshot name dynamically.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 7d4735c..5c0f044 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -172,7 +172,7 @@
/* protects updating the header */
struct rw_semaphore header_rwsem;
- char snap_name[RBD_MAX_SNAP_NAME_LEN];
+ char *snap_name;
u64 snap_id; /* current snapshot id */
int read_only;
@@ -588,8 +588,6 @@
struct ceph_snap_context *snapc = header->snapc;
int ret = -ENOENT;
- BUILD_BUG_ON(sizeof (dev->snap_name) < sizeof (RBD_SNAP_HEAD_NAME));
-
down_write(&dev->header_rwsem);
if (!memcmp(dev->snap_name, RBD_SNAP_HEAD_NAME,
@@ -2390,16 +2388,22 @@
sprintf(rbd_dev->obj_md_name, "%s%s", rbd_dev->obj, RBD_SUFFIX);
/*
- * The snapshot name is optional, but it's an error if it's
- * too long. If no snapshot is supplied, fill in the default.
+ * The snapshot name is optional. If none is is supplied,
+ * we use the default value.
*/
- len = copy_token(&buf, rbd_dev->snap_name, sizeof (rbd_dev->snap_name));
- if (!len)
+ rbd_dev->snap_name = dup_token(&buf, &len);
+ if (!rbd_dev->snap_name)
+ goto out_err;
+ if (!len) {
+ /* Replace the empty name with the default */
+ kfree(rbd_dev->snap_name);
+ rbd_dev->snap_name
+ = kmalloc(sizeof (RBD_SNAP_HEAD_NAME), GFP_KERNEL);
+ if (!rbd_dev->snap_name)
+ goto out_err;
+
memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
sizeof (RBD_SNAP_HEAD_NAME));
- else if (len >= sizeof (rbd_dev->snap_name)) {
- ret = -EINVAL;
- goto out_err;
}
return 0;
@@ -2509,6 +2513,7 @@
rbd_put_client(rbd_dev);
err_put_id:
if (rbd_dev->pool_name) {
+ kfree(rbd_dev->snap_name);
kfree(rbd_dev->obj_md_name);
kfree(rbd_dev->obj);
kfree(rbd_dev->pool_name);
@@ -2561,6 +2566,7 @@
unregister_blkdev(rbd_dev->major, rbd_dev->name);
/* done with the id, and with the rbd_dev */
+ kfree(rbd_dev->snap_name);
kfree(rbd_dev->obj_md_name);
kfree(rbd_dev->pool_name);
kfree(rbd_dev->obj);