namei.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

	fat_brelse(sb, bh);
	if (!inode)
		return res;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	mark_inode_dirty(inode);
	d_instantiate(dentry, inode);
	return 0;
}

/***** Remove a directory */
int msdos_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct super_block *sb = dir->i_sb;
	struct inode *inode = dentry->d_inode;
	int res,ino;
	struct buffer_head *bh;
	struct msdos_dir_entry *de;

	bh = NULL;
	res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len,
				&bh, &de, &ino);
	if (res < 0)
		goto rmdir_done;
	/*
	 * Check whether the directory is not in use, then check
	 * whether it is empty.
	 */
	res = fat_dir_empty(inode);
	if (res)
		goto rmdir_done;

	de->name[0] = DELETED_FLAG;
	fat_mark_buffer_dirty(sb, bh);
	fat_detach(inode);
	inode->i_nlink = 0;
	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	dir->i_nlink--;
	mark_inode_dirty(inode);
	mark_inode_dirty(dir);
	res = 0;

rmdir_done:
	fat_brelse(sb, bh);
	return res;
}

/***** Make a directory */
int msdos_mkdir(struct inode *dir,struct dentry *dentry,int mode)
{
	struct super_block *sb = dir->i_sb;
	struct buffer_head *bh;
	struct msdos_dir_entry *de;
	struct inode *inode;
	int res,is_hid;
	char msdos_name[MSDOS_NAME];
	int ino;

	res = msdos_format_name(dentry->d_name.name,dentry->d_name.len,
				msdos_name, &MSDOS_SB(sb)->options);
	if (res < 0)
		return res;
	is_hid = (dentry->d_name.name[0]=='.') && (msdos_name[0]!='.');
	/* foo vs .foo situation */
	if (fat_scan(dir,msdos_name,&bh,&de,&ino) >= 0)
		goto out_exist;

	res = msdos_add_entry(dir, msdos_name, &bh, &de, &ino, 1, is_hid);
	if (res)
		goto out_unlock;
	inode = fat_build_inode(dir->i_sb, de, ino, &res);
	if (!inode) {
		fat_brelse(sb, bh);
		goto out_unlock;
	}
	res = 0;

	dir->i_nlink++;
	inode->i_nlink = 2; /* no need to mark them dirty */

	res = fat_new_dir(inode, dir, 0);
	if (res)
		goto mkdir_error;

	fat_brelse(sb, bh);
	d_instantiate(dentry, inode);
	res = 0;

out_unlock:
	return res;

mkdir_error:
	printk(KERN_WARNING "msdos_mkdir: error=%d, attempting cleanup\n", res);
	inode->i_nlink = 0;
	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	dir->i_nlink--;
	mark_inode_dirty(inode);
	mark_inode_dirty(dir);
	de->name[0] = DELETED_FLAG;
	fat_mark_buffer_dirty(sb, bh);
	fat_brelse(sb, bh);
	fat_detach(inode);
	iput(inode);
	goto out_unlock;

out_exist:
	fat_brelse(sb, bh);
	res = -EINVAL;
	goto out_unlock;
}

/***** Unlink a file */
int msdos_unlink( struct inode *dir, struct dentry *dentry)
{
	struct super_block *sb = dir->i_sb;
	struct inode *inode = dentry->d_inode;
	int res,ino;
	struct buffer_head *bh;
	struct msdos_dir_entry *de;

	bh = NULL;
	res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len,
			&bh, &de, &ino);
	if (res < 0)
		goto unlink_done;

	de->name[0] = DELETED_FLAG;
	fat_mark_buffer_dirty(sb, bh);
	fat_detach(inode);
	fat_brelse(sb, bh);
	inode->i_nlink = 0;
	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	mark_inode_dirty(inode);
	mark_inode_dirty(dir);
	res = 0;
unlink_done:
	return res;
}

static int do_msdos_rename(struct inode *old_dir, char *old_name,
    struct dentry *old_dentry,
    struct inode *new_dir,char *new_name, struct dentry *new_dentry,
    struct buffer_head *old_bh,
    struct msdos_dir_entry *old_de, int old_ino, int is_hid)
{
	struct super_block *sb = old_dir->i_sb;
	struct buffer_head *new_bh=NULL,*dotdot_bh=NULL;
	struct msdos_dir_entry *new_de,*dotdot_de;
	struct inode *old_inode,*new_inode;
	int new_ino,dotdot_ino;
	int error;
	int is_dir;

	old_inode = old_dentry->d_inode;
	new_inode = new_dentry->d_inode;
	is_dir = S_ISDIR(old_inode->i_mode);

	if (fat_scan(new_dir,new_name,&new_bh,&new_de,&new_ino)>=0 &&!new_inode)
		goto degenerate_case;
	if (is_dir) {
		if (new_inode) {
			error = fat_dir_empty(new_inode);
			if (error)
				goto out;
		}
		error = fat_scan(old_inode, MSDOS_DOTDOT, &dotdot_bh,
				&dotdot_de, &dotdot_ino);
		if (error < 0) {
			printk(KERN_WARNING
				"MSDOS: %s/%s, get dotdot failed, ret=%d\n",
				old_dentry->d_parent->d_name.name,
				old_dentry->d_name.name, error);
			goto out;
		}
	}
	if (!new_bh) {
		error = msdos_add_entry(new_dir, new_name, &new_bh, &new_de,
					&new_ino, is_dir, is_hid);
		if (error)
			goto out;
	}
	new_dir->i_version = ++event;

	/* There we go */

	if (new_inode)
		fat_detach(new_inode);
	old_de->name[0] = DELETED_FLAG;
	fat_mark_buffer_dirty(sb, old_bh);
	fat_detach(old_inode);
	fat_attach(old_inode, new_ino);
	if (is_hid)
		MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
	else
		MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	mark_inode_dirty(old_inode);
	old_dir->i_version = ++event;
	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
	mark_inode_dirty(old_dir);
	if (new_inode) {
		new_inode->i_nlink--;
		new_inode->i_ctime = CURRENT_TIME;
		mark_inode_dirty(new_inode);
	}
	if (dotdot_bh) {
		dotdot_de->start = CT_LE_W(MSDOS_I(new_dir)->i_logstart);
		dotdot_de->starthi = CT_LE_W((MSDOS_I(new_dir)->i_logstart) >> 16);
		fat_mark_buffer_dirty(sb, dotdot_bh);
		old_dir->i_nlink--;
		mark_inode_dirty(old_dir);
		if (new_inode) {
			new_inode->i_nlink--;
			mark_inode_dirty(new_inode);
		} else {
			new_dir->i_nlink++;
			mark_inode_dirty(new_dir);
		}
	}
	error = 0;
out:
	fat_brelse(sb, new_bh);
	fat_brelse(sb, dotdot_bh);
	return error;

degenerate_case:
	error = -EINVAL;
	if (new_de!=old_de)
		goto out;
	if (is_hid)
		MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
	else
		MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	mark_inode_dirty(old_inode);
	old_dir->i_version = ++event;
	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
	mark_inode_dirty(old_dir);
	return 0;
}

/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
int msdos_rename(struct inode *old_dir,struct dentry *old_dentry,
		 struct inode *new_dir,struct dentry *new_dentry)
{
	struct super_block *sb = old_dir->i_sb;
	struct buffer_head *old_bh;
	struct msdos_dir_entry *old_de;
	int old_ino, error;
	int is_hid,old_hid; /* if new file and old file are hidden */
	char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];

	error = msdos_format_name(old_dentry->d_name.name,
				  old_dentry->d_name.len,old_msdos_name,
				  &MSDOS_SB(old_dir->i_sb)->options);
	if (error < 0)
		goto rename_done;
	error = msdos_format_name(new_dentry->d_name.name,
				  new_dentry->d_name.len,new_msdos_name,
				  &MSDOS_SB(new_dir->i_sb)->options);
	if (error < 0)
		goto rename_done;

	is_hid  = (new_dentry->d_name.name[0]=='.') && (new_msdos_name[0]!='.');
	old_hid = (old_dentry->d_name.name[0]=='.') && (old_msdos_name[0]!='.');
	error = fat_scan(old_dir, old_msdos_name, &old_bh, &old_de, &old_ino);
	if (error < 0)
		goto rename_done;

	error = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
				new_dir, new_msdos_name, new_dentry,
				old_bh, old_de, (ino_t)old_ino, is_hid);
	fat_brelse(sb, old_bh);

rename_done:
	return error;
}


/* The public inode operations for the msdos fs */
struct inode_operations msdos_dir_inode_operations = {
	create:		msdos_create,
	lookup:		msdos_lookup,
	unlink:		msdos_unlink,
	mkdir:		msdos_mkdir,
	rmdir:		msdos_rmdir,
	rename:		msdos_rename,
	setattr:	fat_notify_change,
};

struct super_block *msdos_read_super(struct super_block *sb,void *data, int silent)
{
	struct super_block *res;

	MSDOS_SB(sb)->options.isvfat = 0;
	res = fat_read_super(sb, data, silent, &msdos_dir_inode_operations);
	if (res)
		sb->s_root->d_op = &msdos_dentry_operations;
	return res;
}