On Tue, Feb 13, 2024 at 04:20:04PM +0800, Guoyu Ou wrote:
> When we are checking whether a subvolume is empty in the specified snapshot,
> entries that do not belong to this subvolume should be skipped.
>
> This fixes the following case:
>
> $ bcachefs subvolume create ./sub
> $ cd sub
> $ bcachefs subvolume create ./sub2
> $ bcachefs subvolume snapshot . ./snap
> $ ls -a snap
> . ..
> $ rmdir snap
> rmdir: failed to remove 'snap': Directory not empty
>
> As Kent suggested, we pass 0 in may_delete_deleted_inode() to ignore subvols
> in the subvol we are checking, because inode.bi_subvol is only set on
> subvolume roots, and we can't go through every inode in the subvolume and
> change bi_subvol when taking a snapshot. It makes the check less strict, but
> that's ok, the rest of fsck will still catch it.
>
> Signed-off-by: Guoyu Ou <[email protected]>
> ---
> fs/bcachefs/dirent.c | 7 +++++--
> fs/bcachefs/dirent.h | 2 +-
> fs/bcachefs/inode.c | 2 +-
> 3 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
> index 4ae1e9f002a0..82c5bff01411 100644
> --- a/fs/bcachefs/dirent.c
> +++ b/fs/bcachefs/dirent.c
> @@ -508,7 +508,7 @@ u64 bch2_dirent_lookup(struct bch_fs *c, subvol_inum dir,
> return ret;
> }
>
> -int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 snapshot)
> +int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 subvol,
> u32 snapshot)
> {
> struct btree_iter iter;
> struct bkey_s_c k;
> @@ -518,6 +518,9 @@ int bch2_empty_dir_snapshot(struct btree_trans *trans,
> u64 dir, u32 snapshot)
> SPOS(dir, 0, snapshot),
> POS(dir, U64_MAX), 0, k, ret)
> if (k.k->type == KEY_TYPE_dirent) {
> + struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
> + if (d.v->d_type == DT_SUBVOL &&
> le32_to_cpu(d.v->d_parent_subvol) != subvol)
> + continue;
if (d.v->d_type == DT_SUBVOL && (le32_to_cpu(d.v->d_parent_subvol) != subvol ||
!subvol))
> ret = -ENOTEMPTY;
> break;
> }
> @@ -531,7 +534,7 @@ int bch2_empty_dir_trans(struct btree_trans *trans,
> subvol_inum dir)
> u32 snapshot;
>
> return bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot) ?:
> - bch2_empty_dir_snapshot(trans, dir.inum, snapshot);
> + bch2_empty_dir_snapshot(trans, dir.inum, dir.subvol, snapshot);
> }
>
> int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx)
> diff --git a/fs/bcachefs/dirent.h b/fs/bcachefs/dirent.h
> index 21ffeb78f02e..aeb8207ca9f2 100644
> --- a/fs/bcachefs/dirent.h
> +++ b/fs/bcachefs/dirent.h
> @@ -69,7 +69,7 @@ u64 bch2_dirent_lookup(struct bch_fs *, subvol_inum,
> const struct bch_hash_info *,
> const struct qstr *, subvol_inum *);
>
> -int bch2_empty_dir_snapshot(struct btree_trans *, u64, u32);
> +int bch2_empty_dir_snapshot(struct btree_trans *, u64, u32, u32);
> int bch2_empty_dir_trans(struct btree_trans *, subvol_inum);
> int bch2_readdir(struct bch_fs *, subvol_inum, struct dir_context *);
>
> diff --git a/fs/bcachefs/inode.c b/fs/bcachefs/inode.c
> index 086f0090b03a..84a6e5011032 100644
> --- a/fs/bcachefs/inode.c
> +++ b/fs/bcachefs/inode.c
> @@ -1088,7 +1088,7 @@ static int may_delete_deleted_inode(struct btree_trans
> *trans,
> goto out;
>
> if (S_ISDIR(inode.bi_mode)) {
> - ret = bch2_empty_dir_snapshot(trans, pos.offset, pos.snapshot);
> + ret = bch2_empty_dir_snapshot(trans, pos.offset, 0,
> pos.snapshot);
> if (fsck_err_on(ret == -ENOTEMPTY, c, deleted_inode_is_dir,
> "non empty directory %llu:%u in deleted_inodes
> btree",
> pos.offset, pos.snapshot))
> --
> 2.43.0
>
