new_inode — obtain an inode
| struct inode * new_inode ( | struct super_block * sb ); | 
   Allocates a new inode for given superblock. The default gfp_mask
   for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
   If HIGHMEM pages are unsuitable or it is known that pages allocated
   for the page cache are not reclaimable or migratable,
   mapping_set_gfp_mask must be called with suitable flags on the
   newly created inode's mapping