diff options
Diffstat (limited to 'fs/qnx4/bitmap.c')
| -rw-r--r-- | fs/qnx4/bitmap.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c new file mode 100644 index 0000000..9912539 --- /dev/null +++ b/fs/qnx4/bitmap.c @@ -0,0 +1,165 @@ +/* + * QNX4 file system, Linux implementation. + * + * Version : 0.2.1 + * + * Using parts of the xiafs filesystem. + * + * History : + * + * 28-05-1998 by Richard Frowijn : first release. + * 20-06-1998 by Frank Denis : basic optimisations. + * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap . + * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) . + */ + +#include <linux/config.h> +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/qnx4_fs.h> +#include <linux/stat.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/buffer_head.h> +#include <linux/bitops.h> + +int qnx4_new_block(struct super_block *sb) +{ + return 0; +} + +static void count_bits(register const char *bmPart, register int size, + int *const tf) +{ + char b; + int tot = *tf; + + if (size > QNX4_BLOCK_SIZE) { + size = QNX4_BLOCK_SIZE; + } + do { + b = *bmPart++; + if ((b & 1) == 0) + tot++; + if ((b & 2) == 0) + tot++; + if ((b & 4) == 0) + tot++; + if ((b & 8) == 0) + tot++; + if ((b & 16) == 0) + tot++; + if ((b & 32) == 0) + tot++; + if ((b & 64) == 0) + tot++; + if ((b & 128) == 0) + tot++; + size--; + } while (size != 0); + *tf = tot; +} + +unsigned long qnx4_count_free_blocks(struct super_block *sb) +{ + int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; + int total = 0; + int total_free = 0; + int offset = 0; + int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); + struct buffer_head *bh; + + while (total < size) { + if ((bh = sb_bread(sb, start + offset)) == NULL) { + printk("qnx4: I/O error in counting free blocks\n"); + break; + } + count_bits(bh->b_data, size - total, &total_free); + brelse(bh); + total += QNX4_BLOCK_SIZE; + offset++; + } + + return total_free; +} + +#ifdef CONFIG_QNX4FS_RW + +int qnx4_is_free(struct super_block *sb, long block) +{ + int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; + int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); + struct buffer_head *bh; + const char *g; + int ret = -EIO; + + start += block / (QNX4_BLOCK_SIZE * 8); + QNX4DEBUG(("qnx4: is_free requesting block [%lu], bitmap in block [%lu]\n", + (unsigned long) block, (unsigned long) start)); + (void) size; /* CHECKME */ + bh = sb_bread(sb, start); + if (bh == NULL) { + return -EIO; + } + g = bh->b_data + (block % QNX4_BLOCK_SIZE); + if (((*g) & (1 << (block % 8))) == 0) { + QNX4DEBUG(("qnx4: is_free -> block is free\n")); + ret = 1; + } else { + QNX4DEBUG(("qnx4: is_free -> block is busy\n")); + ret = 0; + } + brelse(bh); + + return ret; +} + +int qnx4_set_bitmap(struct super_block *sb, long block, int busy) +{ + int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1; + int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size); + struct buffer_head *bh; + char *g; + + start += block / (QNX4_BLOCK_SIZE * 8); + QNX4DEBUG(("qnx4: set_bitmap requesting block [%lu], bitmap in block [%lu]\n", + (unsigned long) block, (unsigned long) start)); + (void) size; /* CHECKME */ + bh = sb_bread(sb, start); + if (bh == NULL) { + return -EIO; + } + g = bh->b_data + (block % QNX4_BLOCK_SIZE); + if (busy == 0) { + (*g) &= ~(1 << (block % 8)); + } else { + (*g) |= (1 << (block % 8)); + } + mark_buffer_dirty(bh); + brelse(bh); + + return 0; +} + +static void qnx4_clear_inode(struct inode *inode) +{ + struct qnx4_inode_entry *qnx4_ino = qnx4_raw_inode(inode); + /* What for? */ + memset(qnx4_ino->di_fname, 0, sizeof qnx4_ino->di_fname); + qnx4_ino->di_size = 0; + qnx4_ino->di_num_xtnts = 0; + qnx4_ino->di_mode = 0; + qnx4_ino->di_status = 0; +} + +void qnx4_free_inode(struct inode *inode) +{ + if (inode->i_ino < 1) { + printk("free_inode: inode 0 or nonexistent inode\n"); + return; + } + qnx4_clear_inode(inode); + clear_inode(inode); +} + +#endif |
