Commit 7f76b08a authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Subvolumes may now be renamed 



Files within a subvolume cannot be renamed into another subvolume, but
subvolumes themselves were intended to be.

This implements subvolume renaming - we need to ensure that there's only
a single dirent that points to a subvolume key (not multiple versions in
different snapshots), and we need to ensure that dirent.d_parent_subol
and inode.bi_parent_subvol are updated.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 5f43b013

fs/bcachefs/dirent.c

+40 −26
Original line number Diff line number Diff line
@@ -293,12 +293,10 @@ int bch2_dirent_rename(struct btree_trans *trans, 
	struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;

	struct bpos dst_pos =

		POS(dst_dir.inum, bch2_dirent_hash(dst_hash, dst_name));

	unsigned src_type = 0, dst_type = 0, src_update_flags = 0;

	unsigned src_update_flags = 0;

	bool delete_src, delete_dst;

	int ret = 0;



	if (src_dir.subvol != dst_dir.subvol)

		return -EXDEV;



	memset(src_inum, 0, sizeof(*src_inum));

	memset(dst_inum, 0, sizeof(*dst_inum));
@@ -319,12 +317,6 @@ int bch2_dirent_rename(struct btree_trans *trans, 
	if (ret)

		goto out;



	src_type = bkey_s_c_to_dirent(old_src).v->d_type;



	if (src_type == DT_SUBVOL && mode == BCH_RENAME_EXCHANGE)

		return -EOPNOTSUPP;





	/* Lookup dst: */

	if (mode == BCH_RENAME) {

		/*
@@ -352,11 +344,6 @@ int bch2_dirent_rename(struct btree_trans *trans, 
				bkey_s_c_to_dirent(old_dst), dst_inum);

		if (ret)

			goto out;



		dst_type = bkey_s_c_to_dirent(old_dst).v->d_type;



		if (dst_type == DT_SUBVOL)

			return -EOPNOTSUPP;

	}



	if (mode != BCH_RENAME_EXCHANGE)
@@ -426,28 +413,55 @@ int bch2_dirent_rename(struct btree_trans *trans, 
		}

	}



	if (new_dst->v.d_type == DT_SUBVOL)

		new_dst->v.d_parent_subvol = cpu_to_le32(dst_dir.subvol);



	if ((mode == BCH_RENAME_EXCHANGE) &&

	    new_src->v.d_type == DT_SUBVOL)

		new_src->v.d_parent_subvol = cpu_to_le32(src_dir.subvol);



	ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);

	if (ret)

		goto out;

out_set_src:



	/*

	 * If we're deleting a subvolume, we need to really delete the dirent,

	 * not just emit a whiteout in the current snapshot:

	 * If we're deleting a subvolume we need to really delete the dirent,

	 * not just emit a whiteout in the current snapshot - there can only be

	 * single dirent that points to a given subvolume.

	 *

	 * IOW, we don't maintain multiple versions in different snapshots of

	 * dirents that point to subvolumes - dirents that point to subvolumes

	 * are only visible in one particular subvolume so it's not necessary,

	 * and it would be particularly confusing for fsck to have to deal with.

	 */

	if (src_type == DT_SUBVOL) {

		bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);

		ret = bch2_btree_iter_traverse(&src_iter);

	delete_src = bkey_s_c_to_dirent(old_src).v->d_type == DT_SUBVOL &&

		new_src->k.p.snapshot != old_src.k->p.snapshot;



	delete_dst = old_dst.k &&

		bkey_s_c_to_dirent(old_dst).v->d_type == DT_SUBVOL &&

		new_dst->k.p.snapshot != old_dst.k->p.snapshot;



	if (!delete_src || !bkey_deleted(&new_src->k)) {

		ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);

		if (ret)

			goto out;

	}



		new_src->k.p = src_iter.pos;

		src_update_flags |= BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE;

	if (delete_src) {

		bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);

		ret =   bch2_btree_iter_traverse(&src_iter) ?:

			bch2_btree_delete_at(trans, &src_iter, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);

		if (ret)

			goto out;

	}



	ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);

	if (delete_dst) {

		bch2_btree_iter_set_snapshot(&dst_iter, old_dst.k->p.snapshot);

		ret =   bch2_btree_iter_traverse(&dst_iter) ?:

			bch2_btree_delete_at(trans, &dst_iter, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);

		if (ret)

			goto out;

	}



	if (mode == BCH_RENAME_EXCHANGE)

		*src_offset = new_src->k.p.offset;

fs/bcachefs/fs-common.c

+15 −0
Original line number Diff line number Diff line
@@ -410,6 +410,21 @@ int bch2_rename_trans(struct btree_trans *trans, 
			goto err;

	}



	/* Can't move across subvolumes, unless it's a subvolume root: */

	if (src_dir.subvol != dst_dir.subvol &&

	    (!src_inode_u->bi_subvol ||

	     (dst_inum.inum && !dst_inode_u->bi_subvol))) {

		ret = -EXDEV;

		goto err;

	}



	if (src_inode_u->bi_parent_subvol)

		src_inode_u->bi_parent_subvol = dst_dir.subvol;



	if ((mode == BCH_RENAME_EXCHANGE) &&

	    dst_inode_u->bi_parent_subvol)

		dst_inode_u->bi_parent_subvol = src_dir.subvol;



	src_inode_u->bi_dir		= dst_dir_u->bi_inum;

	src_inode_u->bi_dir_offset	= dst_offset;