rbd: dynamically allocate image header name

There is no need to impose a small limit the length of the header
name recorded for an rbd image in a struct rbd_dev.  Remove the
limitation by allocating space for the header name dynamically.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 92867f3e945c..9b676b3b9ba0 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -55,7 +55,6 @@
 
 #define RBD_MINORS_PER_MAJOR    256             /* max minors per blkdev */
 
-#define RBD_MAX_MD_NAME_LEN     (RBD_MAX_OBJ_NAME_LEN + sizeof(RBD_SUFFIX))
 #define RBD_MAX_SNAP_NAME_LEN   32
 #define RBD_MAX_OPT_LEN         1024
 
@@ -164,7 +163,7 @@ struct rbd_device {
         struct rbd_image_header header;
         char                    obj[RBD_MAX_OBJ_NAME_LEN]; /* rbd image name */
         int                     obj_len;
-        char                    obj_md_name[RBD_MAX_MD_NAME_LEN]; /* hdr nm. */
+        char                    *obj_md_name; /* hdr nm. */
         char                    *pool_name;
         int                     pool_id;
 
@@ -2386,8 +2385,13 @@ static int rbd_add_parse_args(struct rbd_device *rbd_dev,
 
         rbd_dev->obj_len = len;
 
-        BUILD_BUG_ON(RBD_MAX_MD_NAME_LEN
-                                < RBD_MAX_OBJ_NAME_LEN + sizeof (RBD_SUFFIX));
+        /* Create the name of the header object */
+
+        rbd_dev->obj_md_name = kmalloc(len + sizeof (RBD_SUFFIX), GFP_KERNEL);
+        if (!rbd_dev->obj_md_name) {
+                ret = -ENOMEM;
+                goto out_err;
+        }
         sprintf(rbd_dev->obj_md_name, "%s%s", rbd_dev->obj, RBD_SUFFIX);
 
         /*
@@ -2406,6 +2410,7 @@ static int rbd_add_parse_args(struct rbd_device *rbd_dev,
         return 0;
 
 out_err:
+        kfree(rbd_dev->obj_md_name);
         kfree(rbd_dev->pool_name);
         rbd_dev->pool_name = NULL;
 
@@ -2416,22 +2421,22 @@ static ssize_t rbd_add(struct bus_type *bus,
                        const char *buf,
                        size_t count)
 {
-        struct rbd_device *rbd_dev;
+        char *options;
+        struct rbd_device *rbd_dev = NULL;
         const char *mon_addrs = NULL;
         size_t mon_addrs_size = 0;
-        char *options = NULL;
         struct ceph_osd_client *osdc;
         int rc = -ENOMEM;
 
         if (!try_module_get(THIS_MODULE))
                 return -ENODEV;
 
-        rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
-        if (!rbd_dev)
-                goto err_nomem;
         options = kmalloc(count, GFP_KERNEL);
         if (!options)
                 goto err_nomem;
+        rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
+        if (!rbd_dev)
+                goto err_nomem;
 
         /* static rbd_device initialization */
         spin_lock_init(&rbd_dev->lock);
@@ -2507,11 +2512,14 @@ err_out_blkdev:
 err_out_client:
         rbd_put_client(rbd_dev);
 err_put_id:
-        kfree(rbd_dev->pool_name);
+        if (rbd_dev->pool_name) {
+                kfree(rbd_dev->obj_md_name);
+                kfree(rbd_dev->pool_name);
+        }
         rbd_id_put(rbd_dev);
 err_nomem:
-        kfree(options);
         kfree(rbd_dev);
+        kfree(options);
 
         dout("Error adding device %s\n", buf);
         module_put(THIS_MODULE);
@@ -2556,6 +2564,7 @@ static void rbd_dev_release(struct device *dev)
         unregister_blkdev(rbd_dev->major, rbd_dev->name);
 
         /* done with the id, and with the rbd_dev */
+        kfree(rbd_dev->obj_md_name);
         kfree(rbd_dev->pool_name);
         rbd_id_put(rbd_dev);
         kfree(rbd_dev);