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Commit 2b8d99a7 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
Browse files

Btrfs: symlinks and hard links 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent e06afa83

fs/btrfs/super.c

+147 −16
Original line number Diff line number Diff line
@@ -26,11 +26,13 @@ struct btrfs_iget_args { 
#define BTRFS_SUPER_MAGIC 0x9123682E



static struct inode_operations btrfs_dir_inode_operations;

static struct inode_operations btrfs_symlink_inode_operations;

static struct inode_operations btrfs_dir_ro_inode_operations;

static struct super_operations btrfs_super_ops;

static struct file_operations btrfs_dir_file_operations;

static struct inode_operations btrfs_file_inode_operations;

static struct address_space_operations btrfs_aops;

static struct address_space_operations btrfs_symlink_aops;

static struct file_operations btrfs_file_operations;



static void btrfs_read_locked_inode(struct inode *inode)
@@ -103,7 +105,8 @@ static void btrfs_read_locked_inode(struct inode *inode) 
			inode->i_op = &btrfs_dir_inode_operations;

		break;

	case S_IFLNK:

		// inode->i_op = &page_symlink_inode_operations;

		inode->i_op = &btrfs_symlink_inode_operations;

		inode->i_mapping->a_ops = &btrfs_symlink_aops;

		break;

	}

	return;
@@ -940,6 +943,41 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry, 
	return err;

}



static int btrfs_link(struct dentry *old_dentry, struct inode *dir,

		      struct dentry *dentry)

{

	struct btrfs_trans_handle *trans;

	struct btrfs_root *root = BTRFS_I(dir)->root;

	struct inode *inode = old_dentry->d_inode;

	int err;

	int drop_inode = 0;



	if (inode->i_nlink == 0)

		return -ENOENT;



	inc_nlink(inode);

	mutex_lock(&root->fs_info->fs_mutex);

	trans = btrfs_start_transaction(root, 1);

	btrfs_set_trans_block_group(trans, dir);

	atomic_inc(&inode->i_count);

	err = btrfs_add_nondir(trans, dentry, inode);

	if (err)

		drop_inode = 1;

	dir->i_sb->s_dirt = 1;

	btrfs_update_inode_block_group(trans, dir);

	btrfs_update_inode(trans, root, inode);



	btrfs_end_transaction(trans, root);

	mutex_unlock(&root->fs_info->fs_mutex);



	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root);

	return err;

}



static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,

				struct btrfs_root *root,

				u64 objectid, u64 dirid)
@@ -2577,33 +2615,25 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry, 
	}





	ret = btrfs_add_link(trans, new_dentry, old_inode);

	if (ret == -EEXIST && new_inode)

		ret = 0;

	else if (ret)

		goto out_fail;



	ret = btrfs_unlink_trans(trans, root, old_dir, old_dentry);

	if (ret)

		goto out_fail;



	if (new_inode) {

		new_inode->i_ctime = CURRENT_TIME;

		di = btrfs_lookup_dir_index_item(trans, root, path,

						 new_dir->i_ino,

						 new_inode->i_ino,

						 new_dentry->d_name.name,

						 new_dentry->d_name.len, -1);

		if (di && !IS_ERR(di)) {

			btrfs_del_item(trans, root, path);

			btrfs_release_path(root, path);

		}

		ret = btrfs_unlink_trans(trans, root, new_dir, new_dentry);

		if (ret)

			goto out_fail;

		if (S_ISDIR(new_inode->i_mode))

			clear_nlink(new_inode);

		else

			drop_nlink(new_inode);

		btrfs_update_inode(trans, root, new_inode);

	}

	ret = btrfs_add_link(trans, new_dentry, old_inode);

	if (ret)

		goto out_fail;



out_fail:

	btrfs_free_path(path);

	btrfs_end_transaction(trans, root);
@@ -2611,6 +2641,94 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry, 
	return ret;

}



static int btrfs_symlink(struct inode *dir, struct dentry *dentry,

			 const char *symname)

{

	struct btrfs_trans_handle *trans;

	struct btrfs_root *root = BTRFS_I(dir)->root;

	struct btrfs_path *path;

	struct btrfs_key key;

	struct inode *inode;

	int err;

	int drop_inode = 0;

	u64 objectid;

	int name_len;

	int datasize;

	char *ptr;

	struct btrfs_file_extent_item *ei;



	name_len = strlen(symname) + 1;

	if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))

		return -ENAMETOOLONG;

	mutex_lock(&root->fs_info->fs_mutex);

	trans = btrfs_start_transaction(root, 1);

	btrfs_set_trans_block_group(trans, dir);



	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);

	if (err) {

		err = -ENOSPC;

		goto out_unlock;

	}



	inode = btrfs_new_inode(trans, root, objectid,

				BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO);

	err = PTR_ERR(inode);

	if (IS_ERR(inode))

		goto out_unlock;



	btrfs_set_trans_block_group(trans, inode);

	err = btrfs_add_nondir(trans, dentry, inode);

	if (err)

		drop_inode = 1;

	else {

		inode->i_mapping->a_ops = &btrfs_aops;

		inode->i_fop = &btrfs_file_operations;

		inode->i_op = &btrfs_file_inode_operations;

	}

	dir->i_sb->s_dirt = 1;

	btrfs_update_inode_block_group(trans, inode);

	btrfs_update_inode_block_group(trans, dir);

	if (drop_inode)

		goto out_unlock;



	path = btrfs_alloc_path();

	BUG_ON(!path);

	key.objectid = inode->i_ino;

	key.offset = 0;

	key.flags = 0;

	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);

	datasize = btrfs_file_extent_calc_inline_size(name_len);

	err = btrfs_insert_empty_item(trans, root, path, &key,

				      datasize);

	BUG_ON(err);

	ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),

	       path->slots[0], struct btrfs_file_extent_item);

	btrfs_set_file_extent_generation(ei, trans->transid);

	btrfs_set_file_extent_type(ei,

				   BTRFS_FILE_EXTENT_INLINE);

	ptr = btrfs_file_extent_inline_start(ei);

	btrfs_memcpy(root, path->nodes[0]->b_data,

		     ptr, symname, name_len);

	mark_buffer_dirty(path->nodes[0]);

	btrfs_free_path(path);

	inode->i_op = &btrfs_symlink_inode_operations;

	inode->i_mapping->a_ops = &btrfs_symlink_aops;

	inode->i_size = name_len - 1;

	btrfs_update_inode(trans, root, inode);

	err = 0;



out_unlock:

	btrfs_end_transaction(trans, root);

	mutex_unlock(&root->fs_info->fs_mutex);



	if (drop_inode) {

		inode_dec_link_count(inode);

		iput(inode);

	}

	btrfs_btree_balance_dirty(root);

	return err;

}



static struct file_system_type btrfs_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "btrfs",
@@ -2636,9 +2754,11 @@ static struct inode_operations btrfs_dir_inode_operations = { 
	.lookup		= btrfs_lookup,

	.create		= btrfs_create,

	.unlink		= btrfs_unlink,

	.link		= btrfs_link,

	.mkdir		= btrfs_mkdir,

	.rmdir		= btrfs_rmdir,

	.rename		= btrfs_rename,

	.symlink	= btrfs_symlink,

};



static struct inode_operations btrfs_dir_ro_inode_operations = {
@@ -2660,6 +2780,11 @@ static struct address_space_operations btrfs_aops = { 
	.commit_write	= btrfs_commit_write,

};



static struct address_space_operations btrfs_symlink_aops = {

	.readpage	= btrfs_readpage,

	.writepage	= btrfs_writepage,

};



static struct inode_operations btrfs_file_inode_operations = {

	.truncate	= btrfs_truncate,

	.getattr	= btrfs_getattr,
@@ -2676,6 +2801,12 @@ static struct file_operations btrfs_file_operations = { 
	.fsync		= btrfs_sync_file,

};



static struct inode_operations btrfs_symlink_inode_operations = {

	.readlink	= generic_readlink,

	.follow_link	= page_follow_link_light,

	.put_link	= page_put_link,

};



static int __init init_btrfs_fs(void)

{

	int err;