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/config.h> 17 #include <linux/time.h> 18 #include <linux/fs.h> 19 #include <linux/qnx4_fs.h> 20 #include <linux/stat.h> 21 #include <linux/kernel.h> 22 #include <linux/string.h> 23 #include <linux/buffer_head.h> 24 #include <linux/bitops.h> 25 26 #if 0 27 int qnx4_new_block(struct super_block *sb) 28 { 29 return 0; 30 } 31 #endif /* 0 */ 32 33 static void count_bits(register const char *bmPart, register int size, 34 int *const tf) 35 { 36 char b; 37 int tot = *tf; 38 39 if (size > QNX4_BLOCK_SIZE) { 40 size = QNX4_BLOCK_SIZE; 41 } 42 do { 43 b = *bmPart++; 44 if ((b & 1) == 0) 45 tot++; 46 if ((b & 2) == 0) 47 tot++; 48 if ((b & 4) == 0) 49 tot++; 50 if ((b & 8) == 0) 51 tot++; 52 if ((b & 16) == 0) 53 tot++; 54 if ((b & 32) == 0) 55 tot++; 56 if ((b & 64) == 0) 57 tot++; 58 if ((b & 128) == 0) 59 tot++; 60 size--; 61 } while (size != 0); 62 *tf = tot; 63 } 64 65 unsigned long qnx4_count_free_blocks(struct super_block *sb) 66 { 67 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; 68 int total = 0; 69 int total_free = 0; 70 int offset = 0; 71 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); 72 struct buffer_head *bh; 73 74 while (total < size) { 75 if ((bh = sb_bread(sb, start + offset)) == NULL) { 76 printk("qnx4: I/O error in counting free blocks\n"); 77 break; 78 } 79 count_bits(bh->b_data, size - total, &total_free); 80 brelse(bh); 81 total += QNX4_BLOCK_SIZE; 82 offset++; 83 } 84 85 return total_free; 86 } 87 88 #ifdef CONFIG_QNX4FS_RW 89 90 int qnx4_is_free(struct super_block *sb, long block) 91 { 92 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; 93 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); 94 struct buffer_head *bh; 95 const char *g; 96 int ret = -EIO; 97 98 start += block / (QNX4_BLOCK_SIZE * 8); 99 QNX4DEBUG(("qnx4: is_free requesting block [%lu], bitmap in block [%lu]\n", 100 (unsigned long) block, (unsigned long) start)); 101 (void) size; /* CHECKME */ 102 bh = sb_bread(sb, start); 103 if (bh == NULL) { 104 return -EIO; 105 } 106 g = bh->b_data + (block % QNX4_BLOCK_SIZE); 107 if (((*g) & (1 << (block % 8))) == 0) { 108 QNX4DEBUG(("qnx4: is_free -> block is free\n")); 109 ret = 1; 110 } else { 111 QNX4DEBUG(("qnx4: is_free -> block is busy\n")); 112 ret = 0; 113 } 114 brelse(bh); 115 116 return ret; 117 } 118 119 int qnx4_set_bitmap(struct super_block *sb, long block, int busy) 120 { 121 int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; 122 int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); 123 struct buffer_head *bh; 124 char *g; 125 126 start += block / (QNX4_BLOCK_SIZE * 8); 127 QNX4DEBUG(("qnx4: set_bitmap requesting block [%lu], bitmap in block [%lu]\n", 128 (unsigned long) block, (unsigned long) start)); 129 (void) size; /* CHECKME */ 130 bh = sb_bread(sb, start); 131 if (bh == NULL) { 132 return -EIO; 133 } 134 g = bh->b_data + (block % QNX4_BLOCK_SIZE); 135 if (busy == 0) { 136 (*g) &= ~(1 << (block % 8)); 137 } else { 138 (*g) |= (1 << (block % 8)); 139 } 140 mark_buffer_dirty(bh); 141 brelse(bh); 142 143 return 0; 144 } 145 146 static void qnx4_clear_inode(struct inode *inode) 147 { 148 struct qnx4_inode_entry *qnx4_ino = qnx4_raw_inode(inode); 149 /* What for? */ 150 memset(qnx4_ino->di_fname, 0, sizeof qnx4_ino->di_fname); 151 qnx4_ino->di_size = 0; 152 qnx4_ino->di_num_xtnts = 0; 153 qnx4_ino->di_mode = 0; 154 qnx4_ino->di_status = 0; 155 } 156 157 void qnx4_free_inode(struct inode *inode) 158 { 159 if (inode->i_ino < 1) { 160 printk("free_inode: inode 0 or nonexistent inode\n"); 161 return; 162 } 163 qnx4_clear_inode(inode); 164 clear_inode(inode); 165 } 166 167 #endif 168