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>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 92867f3..9b676b3 100644 (file)
--- 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);