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Commit f60a2364 authored by Misono Tomohiro's avatar Misono Tomohiro Committed by David Sterba
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btrfs: Factor out the main deletion process from btrfs_ioctl_snap_destroy() 



Factor out the second half of btrfs_ioctl_snap_destroy() as
btrfs_delete_subvolume(), which performs some subvolume specific checks
before deletion:

1. send is not in progress
2. the subvolume is not the default subvolume
3. the subvolume does not contain other subvolumes

and actual deletion process. btrfs_delete_subvolume() requires
inode_lock for both @dir and inode of @dentry. The remaining part of
btrfs_ioctl_snap_destroy() is mainly permission checks.

Note that call of d_delete() is not included in btrfs_delete_subvolume()
as this function will also be used by btrfs_rmdir() to delete an empty
subvolume and in that case d_delete() is called in VFS layer.

As a result, btrfs_unlink_subvol() and may_destroy_subvol()
become static functions. No functional changes.

Signed-off-by: default avatarTomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
[ minor comment updates ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ec42f167

fs/btrfs/ctree.h

+1 −5
Original line number Diff line number Diff line
@@ -3193,11 +3193,7 @@ int btrfs_unlink_inode(struct btrfs_trans_handle *trans, 
int btrfs_add_link(struct btrfs_trans_handle *trans,

		   struct btrfs_inode *parent_inode, struct btrfs_inode *inode,

		   const char *name, int name_len, int add_backref, u64 index);

int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,

			struct btrfs_root *root,

			struct inode *dir, u64 objectid,

			const char *name, int name_len);

noinline int may_destroy_subvol(struct btrfs_root *root);

int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry);

int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,

			int front);

int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,

fs/btrfs/inode.c

+141 −2
Original line number Diff line number Diff line
@@ -4245,7 +4245,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry) 
	return ret;

}



int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,

static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,

			struct btrfs_root *root,

			struct inode *dir, u64 objectid,

			const char *name, int name_len)
@@ -4330,7 +4330,7 @@ int btrfs_unlink_subvol(struct btrfs_trans_handle *trans, 
 * Helper to check if the subvolume references other subvolumes or if it's

 * default.

 */

noinline int may_destroy_subvol(struct btrfs_root *root)

static noinline int may_destroy_subvol(struct btrfs_root *root)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct btrfs_path *path;
@@ -4381,6 +4381,145 @@ noinline int may_destroy_subvol(struct btrfs_root *root) 
	return ret;

}



int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)

{

	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);

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

	struct inode *inode = d_inode(dentry);

	struct btrfs_root *dest = BTRFS_I(inode)->root;

	struct btrfs_trans_handle *trans;

	struct btrfs_block_rsv block_rsv;

	u64 root_flags;

	u64 qgroup_reserved;

	int ret;

	int err;



	/*

	 * Don't allow to delete a subvolume with send in progress. This is

	 * inside the inode lock so the error handling that has to drop the bit

	 * again is not run concurrently.

	 */

	spin_lock(&dest->root_item_lock);

	root_flags = btrfs_root_flags(&dest->root_item);

	if (dest->send_in_progress == 0) {

		btrfs_set_root_flags(&dest->root_item,

				root_flags | BTRFS_ROOT_SUBVOL_DEAD);

		spin_unlock(&dest->root_item_lock);

	} else {

		spin_unlock(&dest->root_item_lock);

		btrfs_warn(fs_info,

			   "attempt to delete subvolume %llu during send",

			   dest->root_key.objectid);

		return -EPERM;

	}



	down_write(&fs_info->subvol_sem);



	err = may_destroy_subvol(dest);

	if (err)

		goto out_up_write;



	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);

	/*

	 * One for dir inode,

	 * two for dir entries,

	 * two for root ref/backref.

	 */

	err = btrfs_subvolume_reserve_metadata(root, &block_rsv,

					       5, &qgroup_reserved, true);

	if (err)

		goto out_up_write;



	trans = btrfs_start_transaction(root, 0);

	if (IS_ERR(trans)) {

		err = PTR_ERR(trans);

		goto out_release;

	}

	trans->block_rsv = &block_rsv;

	trans->bytes_reserved = block_rsv.size;



	btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));



	ret = btrfs_unlink_subvol(trans, root, dir,

				dest->root_key.objectid,

				dentry->d_name.name,

				dentry->d_name.len);

	if (ret) {

		err = ret;

		btrfs_abort_transaction(trans, ret);

		goto out_end_trans;

	}



	btrfs_record_root_in_trans(trans, dest);



	memset(&dest->root_item.drop_progress, 0,

		sizeof(dest->root_item.drop_progress));

	dest->root_item.drop_level = 0;

	btrfs_set_root_refs(&dest->root_item, 0);



	if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {

		ret = btrfs_insert_orphan_item(trans,

					fs_info->tree_root,

					dest->root_key.objectid);

		if (ret) {

			btrfs_abort_transaction(trans, ret);

			err = ret;

			goto out_end_trans;

		}

	}



	ret = btrfs_uuid_tree_rem(trans, fs_info, dest->root_item.uuid,

				  BTRFS_UUID_KEY_SUBVOL,

				  dest->root_key.objectid);

	if (ret && ret != -ENOENT) {

		btrfs_abort_transaction(trans, ret);

		err = ret;

		goto out_end_trans;

	}

	if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {

		ret = btrfs_uuid_tree_rem(trans, fs_info,

					  dest->root_item.received_uuid,

					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,

					  dest->root_key.objectid);

		if (ret && ret != -ENOENT) {

			btrfs_abort_transaction(trans, ret);

			err = ret;

			goto out_end_trans;

		}

	}



out_end_trans:

	trans->block_rsv = NULL;

	trans->bytes_reserved = 0;

	ret = btrfs_end_transaction(trans);

	if (ret && !err)

		err = ret;

	inode->i_flags |= S_DEAD;

out_release:

	btrfs_subvolume_release_metadata(fs_info, &block_rsv);

out_up_write:

	up_write(&fs_info->subvol_sem);

	if (err) {

		spin_lock(&dest->root_item_lock);

		root_flags = btrfs_root_flags(&dest->root_item);

		btrfs_set_root_flags(&dest->root_item,

				root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);

		spin_unlock(&dest->root_item_lock);

	} else {

		d_invalidate(dentry);

		btrfs_invalidate_inodes(dest);

		ASSERT(dest->send_in_progress == 0);



		/* the last ref */

		if (dest->ino_cache_inode) {

			iput(dest->ino_cache_inode);

			dest->ino_cache_inode = NULL;

		}

	}



	return err;

}



static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)

{

	struct inode *inode = d_inode(dentry);

fs/btrfs/ioctl.c

+2 −129
Original line number Diff line number Diff line
@@ -2255,12 +2255,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, 
	struct btrfs_root *root = BTRFS_I(dir)->root;

	struct btrfs_root *dest = NULL;

	struct btrfs_ioctl_vol_args *vol_args;

	struct btrfs_trans_handle *trans;

	struct btrfs_block_rsv block_rsv;

	u64 root_flags;

	u64 qgroup_reserved;

	int namelen;

	int ret;

	int err = 0;



	if (!S_ISDIR(dir->i_mode))
@@ -2344,133 +2339,11 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, 
	}



	inode_lock(inode);



	/*

	 * Don't allow to delete a subvolume with send in progress. This is

	 * inside the i_mutex so the error handling that has to drop the bit

	 * again is not run concurrently.

	 */

	spin_lock(&dest->root_item_lock);

	root_flags = btrfs_root_flags(&dest->root_item);

	if (dest->send_in_progress == 0) {

		btrfs_set_root_flags(&dest->root_item,

				root_flags | BTRFS_ROOT_SUBVOL_DEAD);

		spin_unlock(&dest->root_item_lock);

	} else {

		spin_unlock(&dest->root_item_lock);

		btrfs_warn(fs_info,

			   "Attempt to delete subvolume %llu during send",

			   dest->root_key.objectid);

		err = -EPERM;

		goto out_unlock_inode;

	}



	down_write(&fs_info->subvol_sem);



	err = may_destroy_subvol(dest);

	if (err)

		goto out_up_write;



	btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);

	/*

	 * One for dir inode, two for dir entries, two for root

	 * ref/backref.

	 */

	err = btrfs_subvolume_reserve_metadata(root, &block_rsv,

					       5, &qgroup_reserved, true);

	if (err)

		goto out_up_write;



	trans = btrfs_start_transaction(root, 0);

	if (IS_ERR(trans)) {

		err = PTR_ERR(trans);

		goto out_release;

	}

	trans->block_rsv = &block_rsv;

	trans->bytes_reserved = block_rsv.size;



	btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));



	ret = btrfs_unlink_subvol(trans, root, dir,

				dest->root_key.objectid,

				dentry->d_name.name,

				dentry->d_name.len);

	if (ret) {

		err = ret;

		btrfs_abort_transaction(trans, ret);

		goto out_end_trans;

	}



	btrfs_record_root_in_trans(trans, dest);



	memset(&dest->root_item.drop_progress, 0,

		sizeof(dest->root_item.drop_progress));

	dest->root_item.drop_level = 0;

	btrfs_set_root_refs(&dest->root_item, 0);



	if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {

		ret = btrfs_insert_orphan_item(trans,

					fs_info->tree_root,

					dest->root_key.objectid);

		if (ret) {

			btrfs_abort_transaction(trans, ret);

			err = ret;

			goto out_end_trans;

		}

	}



	ret = btrfs_uuid_tree_rem(trans, fs_info, dest->root_item.uuid,

				  BTRFS_UUID_KEY_SUBVOL,

				  dest->root_key.objectid);

	if (ret && ret != -ENOENT) {

		btrfs_abort_transaction(trans, ret);

		err = ret;

		goto out_end_trans;

	}

	if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {

		ret = btrfs_uuid_tree_rem(trans, fs_info,

					  dest->root_item.received_uuid,

					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,

					  dest->root_key.objectid);

		if (ret && ret != -ENOENT) {

			btrfs_abort_transaction(trans, ret);

			err = ret;

			goto out_end_trans;

		}

	}



out_end_trans:

	trans->block_rsv = NULL;

	trans->bytes_reserved = 0;

	ret = btrfs_end_transaction(trans);

	if (ret && !err)

		err = ret;

	inode->i_flags |= S_DEAD;

out_release:

	btrfs_subvolume_release_metadata(fs_info, &block_rsv);

out_up_write:

	up_write(&fs_info->subvol_sem);

	if (err) {

		spin_lock(&dest->root_item_lock);

		root_flags = btrfs_root_flags(&dest->root_item);

		btrfs_set_root_flags(&dest->root_item,

				root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);

		spin_unlock(&dest->root_item_lock);

	}

out_unlock_inode:

	err = btrfs_delete_subvolume(dir, dentry);

	inode_unlock(inode);

	if (!err) {

		d_invalidate(dentry);

		btrfs_invalidate_inodes(dest);

	if (!err)

		d_delete(dentry);

		ASSERT(dest->send_in_progress == 0);



		/* the last ref */

		if (dest->ino_cache_inode) {

			iput(dest->ino_cache_inode);

			dest->ino_cache_inode = NULL;

		}

	}

out_dput:

	dput(dentry);

out_unlock_dir: