NEX-9200 Improve the scalability of attribute locking in zfs_zget
Reviewed by: Joyce McIntosh <joyce.mcintosh@nexenta.com>
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>

@@ -245,13 +245,13 @@
         } \
 
 /*
  * Macros for dealing with dmu_buf_hold
  */
-#define ZFS_OBJ_HASH(obj_num)   ((obj_num) & (ZFS_OBJ_MTX_SZ - 1))
+#define ZFS_OBJ_HASH(obj_num, table_sz) ((obj_num) & (table_sz - 1))
 #define ZFS_OBJ_MUTEX(zfsvfs, obj_num)  \
-        (&(zfsvfs)->z_hold_mtx[ZFS_OBJ_HASH(obj_num)])
+        (&(zfsvfs)->z_hold_mtx[ZFS_OBJ_HASH(obj_num, (zfsvfs)->z_hold_mtx_sz)])
 #define ZFS_OBJ_HOLD_ENTER(zfsvfs, obj_num) \
         mutex_enter(ZFS_OBJ_MUTEX((zfsvfs), (obj_num)))
 #define ZFS_OBJ_HOLD_TRYENTER(zfsvfs, obj_num) \
         mutex_tryenter(ZFS_OBJ_MUTEX((zfsvfs), (obj_num)))
 #define ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num) \