| /* |
| * linux/fs/ext4/bitmap.c |
| * |
| * Copyright (C) 1992, 1993, 1994, 1995 |
| * Remy Card (card@masi.ibp.fr) |
| * Laboratoire MASI - Institut Blaise Pascal |
| * Universite Pierre et Marie Curie (Paris VI) |
| */ |
| |
| #include <linux/buffer_head.h> |
| #include <linux/jbd2.h> |
| #include "ext4.h" |
| |
| #ifdef EXT4FS_DEBUG |
| |
| static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
| |
| unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars) |
| { |
| unsigned int i, sum = 0; |
| |
| if (!map) |
| return 0; |
| for (i = 0; i < numchars; i++) |
| sum += nibblemap[map->b_data[i] & 0xf] + |
| nibblemap[(map->b_data[i] >> 4) & 0xf]; |
| return sum; |
| } |
| |
| #endif /* EXT4FS_DEBUG */ |
| |
