try_read_node(9)

✨ NAME ✨

try_read_node — read a node if it is a node. Welcome to the try_read_node(9) page, bestie; this one is lowkey niche but highkey useful 💅

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🎀 SYNOPSIS 🎀

int try_read_node (const struct ubifs_info *c , void *buf , int type ,
       struct ubifs_zbranch *zbr );

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🦋 ARGUMENTS 🦋

• c — UBIFS file-system description object. The context baddie.
• buf — buffer to read to. The destination, periodt.
• type — node type.
• zbr — the zbranch describing the node to read.

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🌸 DESCRIPTION 🌸

Okay so picture this: try_read_node tries to read a node of known type and length, checks it, and stores it in buf. That's the whole main-character move ✨

The return vibe check is:

• 1 → a node is present.
• 0 → a node is not present.
• a negative error code → I/O errors. 😭

It performs the same function as ubifs_read_node, except it does not require that there is actually a node present — instead, the return code indicates if a node was read. Very demure, very mindful.

⚠️ CRC caveat, bestie: this function does not check the CRC of data nodes if c->no_chk_data_crc is true (it is controlled by the corresponding mount option). However, if c->mounting or c->remounting_rw is true — meaning we are mounting or re-mounting to R/W mode — then c->no_chk_data_crc is ignored and the CRC is checked. Why? Because during mounting or re-mounting from R/O mode to R/W mode we may read journal nodes (when replying the journal or doing the recovery), and the journal nodes may potentially be corrupted, so checking is required. No cap. 🔥

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💖 SEE ALSO 💖

Kernel file ./fs/ubifs/tnc.c is the home base, and the whole squad is:

• 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), 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)
• dirty_cow_bottom_up(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)

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Source/version cutie: ./fs/ubifs 🌈 date: October 2026 🌸 — that's the try_read_node(9) page, bestie. Slay responsibly! 💅