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 } 59