dbg_chk_lpt_sz(9)

💅 dbg_chk_lpt_sz(9) — the Kernel API Manual glow-up

okay bestie, so this one's from the Kernel API Manual and it's lowkey a little debugging baddie 🎀. Say hi to dbg_chk_lpt_sz 👋 — its whole job is checking that LPT does not write more than the LPT size. That's it. That's the vibe. ✨

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✨ NAME ✨

dbg_chk_lpt_sz — check LPT does not write more than LPT size.

no cap, that's the entire mission statement 💅

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🌸 SYNOPSIS 🌸

int dbg_chk_lpt_sz (struct ubifs_info *c , int action , int len );

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🦋 ARGUMENTS 🦋

• c — the UBIFS file-system description object 🗂️ (the main character of this whole situation)
• action — what to do. which one though? we get into that below, keep reading 💖
• len — length written 📏 (in bytes, bestie)

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🧚 DESCRIPTION 🧚

okay so here's the tea ☕: this function returns 0 on success and a negative error code on failure. Periodt. 💀

The action argument may be one of these five iconic little modes:

• 0 — LPT debugging checking starts, and it initializes the debugging variables 🐣 (we're setting up, it's giving fresh start energy)
• 1 — wrote an LPT node, so increase LPT size by len bytes 📈
• 2 — switched to a different LEB and wasted len bytes 🙈 (oops, bytes gone, nothing we can do)
• 3 — check that we've written the right number of bytes ✅ (the actual vibe check of this entire function)
• 4 — wasted len bytes 🗑️

so like… five moods, one function. she contains multitudes 💜

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🔥 SEE ALSO 🔥

the Kernel file ./fs/ubifs/lpt_commit.c is where the drama lives, and honestly the friend group is huge 🫶:

• first_dirty_cnode(9)
• next_dirty_cnode(9)
• get_cnodes_to_commit(9)
• upd_ltab(9)
• alloc_lpt_leb(9)
• layout_cnodes(9)
• realloc_lpt_leb(9)
• write_cnodes(9)
• next_pnode_to_dirty(9)
• add_pnode_dirt(9)
• do_make_pnode_dirty(9)
• make_tree_dirty(9)
• need_write_all(9)
• lpt_tgc_start(9)
• lpt_tgc_end(9)
• populate_lsave(9)
• nnode_lookup(9)
• make_nnode_dirty(9)
• make_pnode_dirty(9)
• make_ltab_dirty(9)
• make_lsave_dirty(9)
• make_node_dirty(9)
• get_lpt_node_len(9)
• get_pad_len(9)
• get_lpt_node_type(9)
• is_a_node(9)
• lpt_gc_lnum(9)
• lpt_gc(9)
• ubifs_lpt_start_commit(9)
• free_obsolete_cnodes(9)
• ubifs_lpt_end_commit(9)
• ubifs_lpt_post_commit(9)
• first_nnode(9)
• next_nnode(9)
• ubifs_lpt_free(9)
• dbg_is_all_ff(9)
• dbg_is_nnode_dirty(9)
• dbg_is_pnode_dirty(9)
• dbg_is_ltab_dirty(9)
• dbg_is_lsave_dirty(9)
• dbg_is_node_dirty(9)
• dbg_check_ltab_lnum(9)
• dbg_check_ltab(9)
• dbg_chk_lpt_free_spc(9)
• dump_lpt_leb(9)
• ubifs_dump_lpt_lebs(9)
• dbg_populate_lsave(9)

like I said. huge friend group. iykyk 😭👑

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ngl bestie, if you're poking at any of those, you're deep in UBIFS LPT territory — bring snacks 🍓

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and that's the whole page, mwah 💋 — brought to you by the ./fs/ubifs crew, dated October 2026, under the header dbg_chk_lpt_sz(9) from the Kernel API Manual 🎀✨ stay slay, stay debugging 🦋💜