bcachefs: Check subvol <-> inode pointers in check_inode()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 24f8657370ce72e3b4645be0ec8086b34d9c6ef1..120be62331c94e57bb22f41e335bae370125618f 100644 (file)
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -920,6 +920,31 @@ static int check_inode(struct btree_trans *trans,
                do_update = true;
        }
 
+       if (u.bi_subvol) {
+               struct bch_subvolume s;
+
+               ret = bch2_subvolume_get(trans, u.bi_subvol, false, 0, &s);
+               if (ret && !bch2_err_matches(ret, ENOENT))
+                       goto err;
+
+               if (fsck_err_on(ret,
+                               c, inode_bi_subvol_missing,
+                               "inode %llu:%u bi_subvol points to missing subvolume %u",
+                               u.bi_inum, k.k->p.snapshot, u.bi_subvol) ||
+                   fsck_err_on(le64_to_cpu(s.inode) != u.bi_inum ||
+                               !bch2_snapshot_is_ancestor(c, le32_to_cpu(s.snapshot),
+                                                          k.k->p.snapshot),
+                               c, inode_bi_subvol_wrong,
+                               "inode %llu:%u points to subvol %u, but subvol points to %llu:%u",
+                               u.bi_inum, k.k->p.snapshot, u.bi_subvol,
+                               le64_to_cpu(s.inode),
+                               le32_to_cpu(s.snapshot))) {
+                       u.bi_subvol = 0;
+                       u.bi_parent_subvol = 0;
+                       do_update = true;
+               }
+       }
+
        if (do_update) {
                ret = __bch2_fsck_write_inode(trans, &u, iter->pos.snapshot);
                bch_err_msg(c, ret, "in fsck updating inode");