ext4_meta_trans_blocks
extern int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
credits = ext4_meta_trans_blocks(inode, max_blocks, 2);
dio_credits = ext4_meta_trans_blocks(inode, orig_mlen,
ret = ext4_meta_trans_blocks(inode, nrblocks, 1);
return ext4_meta_trans_blocks(inode, nrblocks, 1);