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bcachefs: Subvolumes may now be renamed

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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: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-01-21 16:46:45 -05:00
parent 5f43b0134e
commit 7f76b08aca
2 changed files with 56 additions and 27 deletions
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68
fs/bcachefs/dirent.c
View File

@ -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;
}
ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
if (ret)
goto out;
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;
}
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;

15
fs/bcachefs/fs-common.c
View File

@ -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;