| 1 | /* |
| 2 | * QNX4 file system, Linux implementation. |
| 3 | * |
| 4 | * Version : 0.2.1 |
| 5 | * |
| 6 | * Using parts of the xiafs filesystem. |
| 7 | * |
| 8 | * History : |
| 9 | * |
| 10 | * 28-05-1998 by Richard Frowijn : first release. |
| 11 | * 20-06-1998 by Frank Denis : basic optimisations. |
| 12 | * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap . |
| 13 | * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) . |
| 14 | */ |
| 15 | |
| 16 | #include <linux/buffer_head.h> |
| 17 | #include <linux/bitops.h> |
| 18 | #include "qnx4.h" |
| 19 | |
| 20 | static void count_bits(register const char *bmPart, register int size, |
| 21 | int *const tf) |
| 22 | { |
| 23 | char b; |
| 24 | int tot = *tf; |
| 25 | |
| 26 | if (size > QNX4_BLOCK_SIZE) { |
| 27 | size = QNX4_BLOCK_SIZE; |
| 28 | } |
| 29 | do { |
| 30 | b = *bmPart++; |
| 31 | tot += 8 - hweight8(b); |
| 32 | size--; |
| 33 | } while (size != 0); |
| 34 | *tf = tot; |
| 35 | } |
| 36 | |
| 37 | unsigned long qnx4_count_free_blocks(struct super_block *sb) |
| 38 | { |
| 39 | int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; |
| 40 | int total = 0; |
| 41 | int total_free = 0; |
| 42 | int offset = 0; |
| 43 | int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); |
| 44 | struct buffer_head *bh; |
| 45 | |
| 46 | while (total < size) { |
| 47 | if ((bh = sb_bread(sb, start + offset)) == NULL) { |
| 48 | printk(KERN_ERR "qnx4: I/O error in counting free blocks\n"); |
| 49 | break; |
| 50 | } |
| 51 | count_bits(bh->b_data, size - total, &total_free); |
| 52 | brelse(bh); |
| 53 | total += QNX4_BLOCK_SIZE; |
| 54 | offset++; |
| 55 | } |
| 56 | |
| 57 | return total_free; |
| 58 | } |