inode.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 604 行 · 第 1/2 页

 * of the directory entry.
 */
static const char *qnx4_checkroot(struct super_block *sb)
{
	struct buffer_head *bh;
	struct qnx4_inode_entry *rootdir;
	int rd, rl;
	int i, j;
	int found = 0;

	if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
		return "no qnx4 filesystem (no root dir).";
	} else {
		QNX4DEBUG(("QNX4 filesystem found on dev %s.\n", sb->s_id));
		rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
		rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
		for (j = 0; j < rl; j++) {
			bh = sb_bread(sb, rd + j);	/* root dir, first block */
			if (bh == NULL) {
				return "unable to read root entry.";
			}
			for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
				rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
				if (rootdir->di_fname != NULL) {
					QNX4DEBUG(("Rootdir entry found : [%s]\n", rootdir->di_fname));
					if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
						found = 1;
						qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
						if (!qnx4_sb(sb)->BitMap) {
							brelse (bh);
							return "not enough memory for bitmap inode";
						}
						memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );	/* keep bitmap inode known */
						break;
					}
				}
			}
			brelse(bh);
			if (found != 0) {
				break;
			}
		}
		if (found == 0) {
			return "bitmap file not found.";
		}
	}
	return NULL;
}

static int qnx4_fill_super(struct super_block *s, void *data, int silent)
{
	struct buffer_head *bh;
	struct inode *root;
	const char *errmsg;
	struct qnx4_sb_info *qs;

	qs = kmalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
	if (!qs)
		return -ENOMEM;
	s->s_fs_info = qs;
	memset(qs, 0, sizeof(struct qnx4_sb_info));

	sb_set_blocksize(s, QNX4_BLOCK_SIZE);

	/* Check the superblock signature. Since the qnx4 code is
	   dangerous, we should leave as quickly as possible
	   if we don't belong here... */
	bh = sb_bread(s, 1);
	if (!bh) {
		printk("qnx4: unable to read the superblock\n");
		goto outnobh;
	}
	if ( le32_to_cpu( *(__u32*)bh->b_data ) != QNX4_SUPER_MAGIC ) {
		if (!silent)
			printk("qnx4: wrong fsid in superblock.\n");
		goto out;
	}
	s->s_op = &qnx4_sops;
	s->s_magic = QNX4_SUPER_MAGIC;
#ifndef CONFIG_QNX4FS_RW
	s->s_flags |= MS_RDONLY;	/* Yup, read-only yet */
#endif
	qnx4_sb(s)->sb_buf = bh;
	qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;


 	/* check before allocating dentries, inodes, .. */
	errmsg = qnx4_checkroot(s);
	if (errmsg != NULL) {
 		if (!silent)
 			printk("qnx4: %s\n", errmsg);
		goto out;
	}

 	/* does root not have inode number QNX4_ROOT_INO ?? */
 	root = iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 	if (!root) {
 		printk("qnx4: get inode failed\n");
 		goto out;
 	}

 	s->s_root = d_alloc_root(root);
 	if (s->s_root == NULL)
 		goto outi;

	brelse(bh);

	return 0;

      outi:
	iput(root);
      out:
	brelse(bh);
      outnobh:
	kfree(qs);
	s->s_fs_info = NULL;
	return -EINVAL;
}

static void qnx4_put_super(struct super_block *sb)
{
	struct qnx4_sb_info *qs = qnx4_sb(sb);
	kfree( qs->BitMap );
	kfree( qs );
	sb->s_fs_info = NULL;
	return;
}

static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page,qnx4_get_block, wbc);
}
static int qnx4_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page,qnx4_get_block);
}
static int qnx4_prepare_write(struct file *file, struct page *page,
			      unsigned from, unsigned to)
{
	struct qnx4_inode_info *qnx4_inode = qnx4_i(page->mapping->host);
	return cont_prepare_write(page, from, to, qnx4_get_block,
				  &qnx4_inode->mmu_private);
}
static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping,block,qnx4_get_block);
}
struct address_space_operations qnx4_aops = {
	.readpage	= qnx4_readpage,
	.writepage	= qnx4_writepage,
	.sync_page	= block_sync_page,
	.prepare_write	= qnx4_prepare_write,
	.commit_write	= generic_commit_write,
	.bmap		= qnx4_bmap
};

static void qnx4_read_inode(struct inode *inode)
{
	struct buffer_head *bh;
	struct qnx4_inode_entry *raw_inode;
	int block, ino;
	struct super_block *sb = inode->i_sb;
	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);

	ino = inode->i_ino;
	inode->i_mode = 0;

	QNX4DEBUG(("Reading inode : [%d]\n", ino));
	if (!ino) {
		printk("qnx4: bad inode number on dev %s: %d is out of range\n",
		       sb->s_id, ino);
		return;
	}
	block = ino / QNX4_INODES_PER_BLOCK;

	if (!(bh = sb_bread(sb, block))) {
		printk("qnx4: major problem: unable to read inode from dev "
		       "%s\n", sb->s_id);
		return;
	}
	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
	    (ino % QNX4_INODES_PER_BLOCK);

	inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
	inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
	inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
	inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
	inode->i_size    = le32_to_cpu(raw_inode->di_size);
	inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
	inode->i_mtime.tv_nsec = 0;
	inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
	inode->i_atime.tv_nsec = 0;
	inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
	inode->i_ctime.tv_nsec = 0;
	inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
	inode->i_blksize = QNX4_DIR_ENTRY_SIZE;

	memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
	if (S_ISREG(inode->i_mode)) {
		inode->i_op = &qnx4_file_inode_operations;
		inode->i_fop = &qnx4_file_operations;
		inode->i_mapping->a_ops = &qnx4_aops;
		qnx4_i(inode)->mmu_private = inode->i_size;
	} else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = &qnx4_dir_inode_operations;
		inode->i_fop = &qnx4_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
		inode->i_op = &page_symlink_inode_operations;
		inode->i_mapping->a_ops = &qnx4_aops;
		qnx4_i(inode)->mmu_private = inode->i_size;
	} else
		printk("qnx4: bad inode %d on dev %s\n",ino,sb->s_id);
	brelse(bh);
}

static kmem_cache_t *qnx4_inode_cachep;

static struct inode *qnx4_alloc_inode(struct super_block *sb)
{
	struct qnx4_inode_info *ei;
	ei = kmem_cache_alloc(qnx4_inode_cachep, SLAB_KERNEL);
	if (!ei)
		return NULL;
	return &ei->vfs_inode;
}

static void qnx4_destroy_inode(struct inode *inode)
{
	kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
}

static void init_once(void *foo, kmem_cache_t * cachep,
		      unsigned long flags)
{
	struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;

	if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
	    SLAB_CTOR_CONSTRUCTOR)
		inode_init_once(&ei->vfs_inode);
}

static int init_inodecache(void)
{
	qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
					     sizeof(struct qnx4_inode_info),
					     0, SLAB_RECLAIM_ACCOUNT,
					     init_once, NULL);
	if (qnx4_inode_cachep == NULL)
		return -ENOMEM;
	return 0;
}

static void destroy_inodecache(void)
{
	if (kmem_cache_destroy(qnx4_inode_cachep))
		printk(KERN_INFO
		       "qnx4_inode_cache: not all structures were freed\n");
}

static struct super_block *qnx4_get_sb(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
}

static struct file_system_type qnx4_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "qnx4",
	.get_sb		= qnx4_get_sb,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};

static int __init init_qnx4_fs(void)
{
	int err;

	err = init_inodecache();
	if (err)
		return err;

	err = register_filesystem(&qnx4_fs_type);
	if (err) {
		destroy_inodecache();
		return err;
	}

	printk("QNX4 filesystem 0.2.3 registered.\n");
	return 0;
}

static void __exit exit_qnx4_fs(void)
{
	unregister_filesystem(&qnx4_fs_type);
	destroy_inodecache();
}

module_init(init_qnx4_fs)
module_exit(exit_qnx4_fs)
MODULE_LICENSE("GPL");