dir.c

uclinux的jffs2文件系统

static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char *target)
{
	struct jffs2_inode_info *f, *dir_f;
	struct jffs2_sb_info *c;
	struct inode *inode;
	struct jffs2_raw_inode *ri;
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dnode *fn;
	struct jffs2_full_dirent *fd;
	int namelen;
	__u32 alloclen, phys_ofs;
	__u32 writtenlen;
	int ret;

	/* FIXME: If you care. We'd need to use frags for the target
	   if it grows much more than this */
	if (strlen(target) > 254)
		return -EINVAL;

	ri = jffs2_alloc_raw_inode();

	if (!ri)
		return -ENOMEM;
	
	c = JFFS2_SB_INFO(dir_i->i_sb);
	
	/* Try to reserve enough space for both node and dirent. 
	 * Just the node will do for now, though 
	 */
	namelen = dentry->d_name.len;
	ret = jffs2_reserve_space(c, sizeof(*ri) + strlen(target), &phys_ofs, &alloclen, ALLOC_NORMAL);

	if (ret) {
		jffs2_free_raw_inode(ri);
		return ret;
	}

	inode = jffs2_new_inode(dir_i, S_IFLNK | S_IRWXUGO, ri);

	if (IS_ERR(inode)) {
		jffs2_free_raw_inode(ri);
		jffs2_complete_reservation(c);
		return PTR_ERR(inode);
	}

	inode->i_op = &jffs2_symlink_inode_operations;

	f = JFFS2_INODE_INFO(inode);

	inode->i_size = ri->isize = ri->dsize = ri->csize = strlen(target);
	ri->totlen = sizeof(*ri) + ri->dsize;
	ri->hdr_crc = crc32(0, ri, sizeof(struct jffs2_unknown_node)-4);

	ri->compr = JFFS2_COMPR_NONE;
	ri->data_crc = crc32(0, target, strlen(target));
	ri->node_crc = crc32(0, ri, sizeof(*ri)-8);
	
	fn = jffs2_write_dnode(inode, ri, target, strlen(target), phys_ofs, &writtenlen);

	jffs2_free_raw_inode(ri);

	if (IS_ERR(fn)) {
		/* Eeek. Wave bye bye */
		up(&f->sem);
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return PTR_ERR(fn);
	}
	/* No data here. Only a metadata node, which will be 
	   obsoleted by the first data write
	*/
	f->metadata = fn;
	up(&f->sem);

	/* Work out where to put the dirent node now. */
	writtenlen = (writtenlen+3)&~3;
	phys_ofs += writtenlen;
	alloclen -= writtenlen;

	if (alloclen < sizeof(*rd)+namelen) {
		/* Not enough space left in this chunk. Get some more */
		jffs2_complete_reservation(c);
		ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
		if (ret) {
			/* Eep. */
			jffs2_clear_inode(inode);
			return ret;
		}
	}

	rd = jffs2_alloc_raw_dirent();
	if (!rd) {
		/* Argh. Now we treat it like a normal delete */
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return -ENOMEM;
	}

	dir_f = JFFS2_INODE_INFO(dir_i);
	down(&dir_f->sem);

	rd->magic = JFFS2_MAGIC_BITMASK;
	rd->nodetype = JFFS2_NODETYPE_DIRENT;
	rd->totlen = sizeof(*rd) + namelen;
	rd->hdr_crc = crc32(0, rd, sizeof(struct jffs2_unknown_node)-4);

	rd->pino = dir_i->i_ino;
	rd->version = ++dir_f->highest_version;
	rd->ino = inode->i_ino;
	rd->mctime = CURRENT_TIME;
	rd->nsize = namelen;
	rd->type = DT_LNK;
	rd->node_crc = crc32(0, rd, sizeof(*rd)-8);
	rd->name_crc = crc32(0, dentry->d_name.name, namelen);

	fd = jffs2_write_dirent(dir_i, rd, dentry->d_name.name, namelen, phys_ofs, &writtenlen);
	
	jffs2_complete_reservation(c);
	
	if (IS_ERR(fd)) {
		/* dirent failed to write. Delete the inode normally 
		   as if it were the final unlink() */
		jffs2_free_raw_dirent(rd);
		up(&dir_f->sem);
		jffs2_clear_inode(inode);
		return PTR_ERR(fd);
	}

	dir_i->i_mtime = dir_i->i_ctime = rd->mctime;

	jffs2_free_raw_dirent(rd);

	/* Link the fd into the inode's list, obsoleting an old
	   one if necessary. */
	jffs2_add_fd_to_list(c, fd, &dir_f->dents);
	up(&dir_f->sem);

	d_instantiate(dentry, inode);
	return 0;
}


static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, int mode)
{
	struct jffs2_inode_info *f, *dir_f;
	struct jffs2_sb_info *c;
	struct inode *inode;
	struct jffs2_raw_inode *ri;
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dnode *fn;
	struct jffs2_full_dirent *fd;
	int namelen;
	__u32 alloclen, phys_ofs;
	__u32 writtenlen;
	int ret;

	mode |= S_IFDIR;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;
	
	c = JFFS2_SB_INFO(dir_i->i_sb);

	/* Try to reserve enough space for both node and dirent. 
	 * Just the node will do for now, though 
	 */
	namelen = dentry->d_name.len;
	ret = jffs2_reserve_space(c, sizeof(*ri), &phys_ofs, &alloclen, ALLOC_NORMAL);

	if (ret) {
		jffs2_free_raw_inode(ri);
		return ret;
	}

	inode = jffs2_new_inode(dir_i, mode, ri);

	if (IS_ERR(inode)) {
		jffs2_free_raw_inode(ri);
		jffs2_complete_reservation(c);
		return PTR_ERR(inode);
	}

	inode->i_op = &jffs2_dir_inode_operations;
	inode->i_fop = &jffs2_dir_operations;

	f = JFFS2_INODE_INFO(inode);

	ri->data_crc = 0;
	ri->node_crc = crc32(0, ri, sizeof(*ri)-8);
	
	fn = jffs2_write_dnode(inode, ri, NULL, 0, phys_ofs, &writtenlen);

	jffs2_free_raw_inode(ri);

	if (IS_ERR(fn)) {
		/* Eeek. Wave bye bye */
		up(&f->sem);
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return PTR_ERR(fn);
	}
	/* No data here. Only a metadata node, which will be 
	   obsoleted by the first data write
	*/
	f->metadata = fn;
	up(&f->sem);

	/* Work out where to put the dirent node now. */
	writtenlen = PAD(writtenlen);
	phys_ofs += writtenlen;
	alloclen -= writtenlen;

	if (alloclen < sizeof(*rd)+namelen) {
		/* Not enough space left in this chunk. Get some more */
		jffs2_complete_reservation(c);
		ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
		if (ret) {
			/* Eep. */
			jffs2_clear_inode(inode);
			return ret;
		}
	}
	
	rd = jffs2_alloc_raw_dirent();
	if (!rd) {
		/* Argh. Now we treat it like a normal delete */
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return -ENOMEM;
	}

	dir_f = JFFS2_INODE_INFO(dir_i);
	down(&dir_f->sem);

	rd->magic = JFFS2_MAGIC_BITMASK;
	rd->nodetype = JFFS2_NODETYPE_DIRENT;
	rd->totlen = sizeof(*rd) + namelen;
	rd->hdr_crc = crc32(0, rd, sizeof(struct jffs2_unknown_node)-4);

	rd->pino = dir_i->i_ino;
	rd->version = ++dir_f->highest_version;
	rd->ino = inode->i_ino;
	rd->mctime = CURRENT_TIME;
	rd->nsize = namelen;
	rd->type = DT_DIR;
	rd->node_crc = crc32(0, rd, sizeof(*rd)-8);
	rd->name_crc = crc32(0, dentry->d_name.name, namelen);

	fd = jffs2_write_dirent(dir_i, rd, dentry->d_name.name, namelen, phys_ofs, &writtenlen);
	
	jffs2_complete_reservation(c);
	
	if (IS_ERR(fd)) {
		/* dirent failed to write. Delete the inode normally 
		   as if it were the final unlink() */
		jffs2_free_raw_dirent(rd);
		up(&dir_f->sem);
		jffs2_clear_inode(inode);
		return PTR_ERR(fd);
	}

	dir_i->i_mtime = dir_i->i_ctime = rd->mctime;

	jffs2_free_raw_dirent(rd);

	/* Link the fd into the inode's list, obsoleting an old
	   one if necessary. */
	jffs2_add_fd_to_list(c, fd, &dir_f->dents);
	up(&dir_f->sem);

	d_instantiate(dentry, inode);
	return 0;
}

static int jffs2_rmdir (struct inode *dir_i, struct dentry *dentry)
{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(dentry->d_inode);
	struct jffs2_full_dirent *fd;

	for (fd = f->dents ; fd; fd = fd->next) {
		if (fd->ino)
			return -ENOTEMPTY;
	}
	return jffs2_unlink(dir_i, dentry);
}

static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, int mode, int rdev)
{
	struct jffs2_inode_info *f, *dir_f;
	struct jffs2_sb_info *c;
	struct inode *inode;
	struct jffs2_raw_inode *ri;
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dnode *fn;
	struct jffs2_full_dirent *fd;
	int namelen;
	unsigned short dev;
	int devlen = 0;
	__u32 alloclen, phys_ofs;
	__u32 writtenlen;
	int ret;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;
	
	c = JFFS2_SB_INFO(dir_i->i_sb);
	
	if (S_ISBLK(mode) || S_ISCHR(mode)) {
		dev = (MAJOR(to_kdev_t(rdev)) << 8) | MINOR(to_kdev_t(rdev));
		devlen = sizeof(dev);
	}
	
	/* Try to reserve enough space for both node and dirent. 
	 * Just the node will do for now, though 
	 */
	namelen = dentry->d_name.len;
	ret = jffs2_reserve_space(c, sizeof(*ri) + devlen, &phys_ofs, &alloclen, ALLOC_NORMAL);

	if (ret) {
		jffs2_free_raw_inode(ri);
		return ret;
	}

	inode = jffs2_new_inode(dir_i, mode, ri);

	if (IS_ERR(inode)) {
		jffs2_free_raw_inode(ri);
		jffs2_complete_reservation(c);
		return PTR_ERR(inode);
	}
	inode->i_op = &jffs2_file_inode_operations;
	init_special_inode(inode, inode->i_mode, rdev);

	f = JFFS2_INODE_INFO(inode);

	ri->dsize = ri->csize = devlen;
	ri->totlen = sizeof(*ri) + ri->csize;
	ri->hdr_crc = crc32(0, ri, sizeof(struct jffs2_unknown_node)-4);

	ri->compr = JFFS2_COMPR_NONE;
	ri->data_crc = crc32(0, &dev, devlen);
	ri->node_crc = crc32(0, ri, sizeof(*ri)-8);
	
	fn = jffs2_write_dnode(inode, ri, (char *)&dev, devlen, phys_ofs, &writtenlen);

	jffs2_free_raw_inode(ri);

	if (IS_ERR(fn)) {
		/* Eeek. Wave bye bye */
		up(&f->sem);
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return PTR_ERR(fn);
	}
	/* No data here. Only a metadata node, which will be 
	   obsoleted by the first data write
	*/
	f->metadata = fn;
	up(&f->sem);

	/* Work out where to put the dirent node now. */
	writtenlen = (writtenlen+3)&~3;
	phys_ofs += writtenlen;
	alloclen -= writtenlen;

	if (alloclen < sizeof(*rd)+namelen) {
		/* Not enough space left in this chunk. Get some more */
		jffs2_complete_reservation(c);
		ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
		if (ret) {
			/* Eep. */
			jffs2_clear_inode(inode);
			return ret;
		}
	}

	rd = jffs2_alloc_raw_dirent();
	if (!rd) {
		/* Argh. Now we treat it like a normal delete */
		jffs2_complete_reservation(c);
		jffs2_clear_inode(inode);
		return -ENOMEM;
	}

	dir_f = JFFS2_INODE_INFO(dir_i);
	down(&dir_f->sem);

	rd->magic = JFFS2_MAGIC_BITMASK;
	rd->nodetype = JFFS2_NODETYPE_DIRENT;
	rd->totlen = sizeof(*rd) + namelen;
	rd->hdr_crc = crc32(0, rd, sizeof(struct jffs2_unknown_node)-4);

	rd->pino = dir_i->i_ino;
	rd->version = ++dir_f->highest_version;
	rd->ino = inode->i_ino;
	rd->mctime = CURRENT_TIME;
	rd->nsize = namelen;

	/* XXX: This is ugly. */
	rd->type = (mode & S_IFMT) >> 12;

	rd->node_crc = crc32(0, rd, sizeof(*rd)-8);
	rd->name_crc = crc32(0, dentry->d_name.name, namelen);

	fd = jffs2_write_dirent(dir_i, rd, dentry->d_name.name, namelen, phys_ofs, &writtenlen);
	
	jffs2_complete_reservation(c);
	
	if (IS_ERR(fd)) {
		/* dirent failed to write. Delete the inode normally 
		   as if it were the final unlink() */
		jffs2_free_raw_dirent(rd);
		up(&dir_f->sem);
		jffs2_clear_inode(inode);
		return PTR_ERR(fd);
	}

	dir_i->i_mtime = dir_i->i_ctime = rd->mctime;

	jffs2_free_raw_dirent(rd);

	/* Link the fd into the inode's list, obsoleting an old
	   one if necessary. */
	jffs2_add_fd_to_list(c, fd, &dir_f->dents);
	up(&dir_f->sem);

	d_instantiate(dentry, inode);

	return 0;
}

static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
                        struct inode *new_dir_i, struct dentry *new_dentry)
{
	int ret;
	struct jffs2_inode_info *victim_f = NULL;

	/* The VFS will check for us and prevent trying to rename a 
	 * file over a directory and vice versa, but if it's a directory,
	 * the VFS can't check whether the victim is empty. The filesystem
	 * needs to do that for itself.
	 */
	if (new_dentry->d_inode) {
		victim_f = JFFS2_INODE_INFO(new_dentry->d_inode);
		if (S_ISDIR(new_dentry->d_inode->i_mode)) {
			struct jffs2_full_dirent *fd;

			down(&victim_f->sem);
			for (fd = victim_f->dents; fd; fd = fd->next) {
				if (fd->ino) {
					up(&victim_f->sem);
					return -ENOTEMPTY;
				}
			}
			up(&victim_f->sem);
		}
	}

	/* XXX: We probably ought to alloc enough space for
	   both nodes at the same time. Writing the new link, 
	   then getting -ENOSPC, is quite bad :)
	*/

	/* Make a hard link */
	ret = jffs2_do_link(old_dentry, new_dir_i, new_dentry, 1);
	if (ret)
		return ret;

	if (victim_f) {
		/* There was a victim. Kill it off nicely */
		new_dentry->d_inode->i_nlink--;
		/* Don't oops if the victim was a dirent pointing to an
		   inode which didn't exist. */
		if (victim_f->inocache) {
			down(&victim_f->sem);
			victim_f->inocache->nlink--;
			up(&victim_f->sem);
		}
	}

	/* Unlink the original */
	ret = jffs2_do_unlink(old_dir_i, old_dentry, 1);
	
	if (ret) {
		/* Oh shit. We really ought to make a single node which can do both atomically */
		struct jffs2_inode_info *f = JFFS2_INODE_INFO(old_dentry->d_inode);
		down(&f->sem);
		old_dentry->d_inode->i_nlink = f->inocache->nlink++;
		up(&f->sem);
		       
		printk(KERN_NOTICE "jffs2_rename(): Link succeeded, unlink failed (err %d). You now have a hard link\n", ret);
		/* Might as well let the VFS know */
		d_instantiate(new_dentry, old_dentry->d_inode);
		atomic_inc(&old_dentry->d_inode->i_count);
	}
	return ret;
}