dirty_cow_bottom_up(9)

okay bestie, this is dirty_cow_bottom_up(9) from the Kernel API Manual, section 9 — and it's literally about dirtying a znode and its ancestors ✨

💅 NAME 💅

dirty_cow_bottom_up — dirty a znode and its ancestors. periodt.

🦋 SYNOPSIS 🦋

struct ubifs_znode * dirty_cow_bottom_up (struct ubifs_info *c , struct ubifs_znode *znode );

🎀 ARGUMENTS 🎀

• c — the UBIFS file-system description object. like the main character of the filesystem, yk?
• znode — the znode you wanna dirty. yes bestie, that exact one.

🌸 DESCRIPTION 🌸

okay so here's the tea: if we do not have a unique key that resides in a znode, then we cannot dirty that znode from the top down (i.e. by using lookup_level0_dirty). that's just the vibe, no cap.

so this function records the path back to the last dirty ancestor, and then dirties the znodes on that path. it's giving bottom-up energy, and honestly? iconic.

🔥 SEE ALSO 🔥

bestie, go check out the kernel file ./fs/ubifs/tnc.c and these absolute legends:

• insert_old_idx(9)
• insert_old_idx_znode(9)
• ins_clr_old_idx_znode(9)
• destroy_old_idx(9)
• copy_znode(9)
• add_idx_dirt(9)
• replace_znode(9)
• dirty_cow_znode(9)
• lnc_add(9)
• lnc_free(9)
• tnc_read_hashed_node(9)
• try_read_node(9)
• fallible_read_node(9)
• matches_name(9)
• get_znode(9)
• tnc_next(9)
• tnc_prev(9)
• resolve_collision(9)
• fallible_matches_name(9)
• fallible_resolve_collision(9)
• matches_position(9)
• resolve_collision_directly(9)
• ubifs_lookup_level0(9)
• lookup_level0_dirty(9)
• maybe_leb_gced(9)
• ubifs_tnc_locate(9)
• ubifs_tnc_get_bu_keys(9)
• read_wbuf(9)
• validate_data_node(9)
• ubifs_tnc_bulk_read(9)
• do_lookup_nm(9)
• ubifs_tnc_lookup_nm(9)
• ubifs_tnc_lookup_dh(9)
• correct_parent_keys(9)
• insert_zbranch(9)
• tnc_insert(9)
• ubifs_tnc_add(9)
• ubifs_tnc_replace(9)
• ubifs_tnc_add_nm(9)
• tnc_delete(9)
• ubifs_tnc_remove(9)
• ubifs_tnc_remove_nm(9)
• ubifs_tnc_remove_dh(9)
• key_in_range(9)
• ubifs_tnc_remove_range(9)
• ubifs_tnc_remove_ino(9)
• ubifs_tnc_next_ent(9)
• tnc_destroy_cnext(9)
• ubifs_tnc_close(9)
• left_znode(9)
• right_znode(9)
• lookup_znode(9)
• is_idx_node_in_tnc(9)
• is_leaf_node_in_tnc(9)
• ubifs_tnc_has_node(9)
• ubifs_dirty_idx_node(9)
• dbg_check_inode_size(9)

sending all my love from ./fs/ubifs, October 2026 💖🫶✨