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bcachefs: check dirent->d_parent_subvol

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Check that d_parent_subvol makes sense - the dirent's snapshot must be
visible in d_parent_subvol (i.e. an ancestor of d_parent_subvol's
snapshot) in order to be visible.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
2024-02-07 00:45:09 -05:00
parent f4e68c859f
commit c60b7f803c
1 changed files with 57 additions and 4 deletions
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61
fs/bcachefs/fsck.c
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@@ -1692,6 +1692,31 @@ static int check_dirent_target(struct btree_trans *trans,
return ret;
}
/* find a subvolume that's a descendent of @snapshot: */
static int find_snapshot_subvol(struct btree_trans *trans, u32 snapshot, u32 *subvolid)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret;
for_each_btree_key_norestart(trans, iter, BTREE_ID_subvolumes, POS_MIN, 0, k, ret) {
if (k.k->type != KEY_TYPE_subvolume)
continue;
struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
if (bch2_snapshot_is_ancestor(trans->c, le32_to_cpu(s.v->snapshot), snapshot)) {
bch2_trans_iter_exit(trans, &iter);
*subvolid = k.k->p.offset;
goto found;
}
}
if (!ret)
ret = -ENOENT;
found:
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *iter,
struct bkey_s_c_dirent d)
{
@@ -1699,18 +1724,44 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
struct bch_inode_unpacked subvol_root;
u32 parent_subvol = le32_to_cpu(d.v->d_parent_subvol);
u32 target_subvol = le32_to_cpu(d.v->d_child_subvol);
u32 target_snapshot;
u64 target_inum;
u32 target_snapshot, parent_snapshot;
u64 target_inum, parent_inum;
struct printbuf buf = PRINTBUF;
int ret = 0;
ret = subvol_lookup(trans, parent_subvol, &parent_snapshot, &parent_inum);
if (ret && !bch2_err_matches(ret, ENOENT))
return ret;
if (fsck_err_on(ret, c, dirent_to_missing_parent_subvol,
"dirent parent_subvol points to missing subvolume\n%s",
(bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf)) ||
fsck_err_on(!ret && !bch2_snapshot_is_ancestor(c, parent_snapshot, d.k->p.snapshot),
c, dirent_not_visible_in_parent_subvol,
"dirent not visible in parent_subvol (not an ancestor of subvol snap %u)\n%s",
parent_snapshot,
(bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {
u32 new_parent_subvol;
ret = find_snapshot_subvol(trans, d.k->p.snapshot, &new_parent_subvol);
if (ret)
goto err;
struct bkey_i_dirent *new_dirent = bch2_bkey_make_mut_typed(trans, iter, &d.s_c, 0, dirent);
ret = PTR_ERR_OR_ZERO(new_dirent);
if (ret)
goto err;
new_dirent->v.d_parent_subvol = cpu_to_le32(new_parent_subvol);
}
ret = subvol_lookup(trans, target_subvol,
&target_snapshot, &target_inum);
if (ret && !bch2_err_matches(ret, ENOENT))
return ret;
if (fsck_err_on(ret, c, dirent_to_missing_subvol,
"dirent points to missing subvolume %u",
le32_to_cpu(d.v->d_child_subvol)))
"dirent points to missing subvolume\n%s",
(bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf)))
return __remove_dirent(trans, d.k->p);
ret = lookup_inode(trans, target_inum,
@@ -1733,7 +1784,9 @@ static int check_dirent_to_subvol(struct btree_trans *trans, struct btree_iter *
target_snapshot);
if (ret)
return ret;
err:
fsck_err:
printbuf_exit(&buf);
return ret;
}