vdo_get_save...e_count_size(9)

💅 vdo_get_save...e_count_size(9) — Kernel API Manual 🎀

okay so this is a page from the Kernel API Manual, and bestie, it's a short one — we're looking at vdo_get_saved_reference_count_size in the dm-vdo kernel code. It's giving "tiny function, big responsibility" honestly. Very demure, very mindful. ✨

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🌸 NAME 🌸

vdo_get_saved_reference_count_size — literally just gets you the number of blocks you need to save a reference counts state that covers the specified number of data blocks. that's it. that's the whole job. 💖

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🦋 SYNOPSIS 🦋

block_count_t vdo_get_saved_reference_count_size (block_count_t
block_count );

no cap, that's the whole signature. it takes a block_count_t and hands you back a block_count_t. clean. iconic. 🫶

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✨ ARGUMENTS ✨

• block_count — the number of physical data blocks that can be referenced. like, how many blocks could possibly be pointed at. that's the input, bestie. 💅

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🔥 RETURN 🔥

it returns the number of blocks required to save reference counts with the given block count. so you feed it a block_count, you get back how many blocks of saved-reference-counts storage that maps to. the way that math just works. 🙈

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👑 SEE ALSO 👑

Kernel file ./drivers/md/dm-vdo/encodings.h, plus the whole friend group:

• Block map entries(9)
• vdo_are_same_version(9)
• vdo_pack_version_number(9)
• vdo_unpack_version_number(9)
• vdo_pack_header(9)
• vdo_unpack_header(9)
• vdo_get_index_region_start(9)
• vdo_get_data_region_start(9)
• vdo_get_index_region_size(9)
• vdo_pack_recovery_journal_entry(9)
• vdo_unpack_recovery_journal_entry(9)
• vdo_is_valid_recovery_journal_sector(9)
• vdo_compute_recovery_journal_block_number(9)
• vdo_get_journal_block_sector(9)
• vdo_pack_recovery_block_header(9)
• vdo_unpack_recovery_block_header(9)
• vdo_compute_slab_count(9)
• vdo_get_slab_journal_start_block(9)
• vdo_advance_journal_point(9)
• vdo_before_journal_point(9)
• vdo_pack_journal_point(9)
• vdo_unpack_journal_point(9)
• vdo_pack_slab_journal_block_header(9)
• vdo_unpack_slab_journal_block_header(9)
• vdo_pack_slab_journal_entry(9)
• vdo_unpack_slab_journal_entry(9)
• vdo_get_slab_summary_hint_shift(9)

that's the whole squad fr fr, go read them all, they're all in ./drivers/md/dm-vdo and they all ate. 🌈

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and that's the page!! sourced from ./drivers/md/dm-vdo, October 2026 edition, manual name vdo_get_save...e_count_size(9) — mwah, go forth and count your blocks, bestie 💜🎀⭐