| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/ext4/bitmap.c |
| 3 | * |
| 4 | * Copyright (C) 1992, 1993, 1994, 1995 |
| 5 | * Remy Card (card@masi.ibp.fr) |
| 6 | * Laboratoire MASI - Institut Blaise Pascal |
| 7 | * Universite Pierre et Marie Curie (Paris VI) |
| 8 | */ |
| 9 | |
| 10 | #include <linux/buffer_head.h> |
| 11 | #include <linux/jbd2.h> |
| 12 | #include "ext4.h" |
| 13 | |
| 14 | static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
| 15 | |
| 16 | unsigned int ext4_count_free(char *bitmap, unsigned int numchars) |
| 17 | { |
| 18 | unsigned int i, sum = 0; |
| 19 | |
| 20 | for (i = 0; i < numchars; i++) |
| 21 | sum += nibblemap[bitmap[i] & 0xf] + |
| 22 | nibblemap[(bitmap[i] >> 4) & 0xf]; |
| 23 | return sum; |
| 24 | } |
| 25 | |