rgd_free(9)

🦋 rgd_free(9) — the Kernel API Manual page, bestie edition ✨

okay so this is a page from the Kernel API Manual and it's all about rgd_free, which ngl is a whole little icon in the GFS2 resource-group world. sit down, grab a strawberry 🍓, we're learning.

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🌸 NAME 🌸

rgd_free — literally just returns the number of free blocks we can allocate 💅

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✨ SYNOPSIS ✨

u32 rgd_free (struct gfs2_rgrpd *rgd , struct gfs2_blkreserv *rs );

that's the whole signature, no cap — it gives you back a u32 🫶

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🎀 ARGUMENTS 🎀

• rgd — the resource group 👑 this is the rgrp we're doing the math on.
• rs — the reservation to free 💖

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🧚 DESCRIPTION 🧚

okay so here's the vibe: this function returns the number of free blocks for an rgrp. periodt.

and like, which free blocks? the clone-free blocks — that means blocks that are free, not counting the ones still being used for unlinked files that haven't been deleted yet. they're lowkey still busy, so they don't count 🙈

it also subtracts any blocks that somebody else reserved, because those are spoken for, not yours, respect the boundaries bestie 💅

but — and this is the main character detail — it does not include free blocks that are still part of our current reservation. why? because obviously we can (and will) allocate them. it's giving "yes that's mine, next question" 🔥

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🌈 SEE ALSO 🌈

this list is long and honestly iconic, so buckle up 🦋 it's the Kernel file ./fs/gfs2/rgrp.c plus, like, everyone it hangs out with:

• gfs2_setbit(9), gfs2_testbit(9), gfs2_bit_search(9), rs_cmp(9), gfs2_bitfit(9), gfs2_rbm_from_block(9), gfs2_rbm_add(9), gfs2_unaligned_extlen(9), gfs2_free_extlen(9), gfs2_bitcount(9), gfs2_rgrp_verify(9), gfs2_blk2rgrpd(9), gfs2_rgrpd_get_first(9), gfs2_rgrpd_get_next(9), __rs_deltree(9), gfs2_rs_deltree(9), gfs2_rs_delete(9), return_all_reservations(9), compute_bitstructs(9), gfs2_ri_total(9), read_rindex_entry(9), set_rgrp_preferences(9), gfs2_ri_update(9), gfs2_rindex_update(9), gfs2_rgrp_go_instantiate(9), gfs2_rgrp_brelse(9), gfs2_fitrim(9), rs_insert(9), rg_mblk_search(9), gfs2_next_unreserved_block(9), gfs2_reservation_check_and_update(9), gfs2_rbm_find(9), try_rgrp_unlink(9), gfs2_rgrp_congested(9), gfs2_rgrp_used_recently(9), fast_to_acquire(9), gfs2_inplace_reserve(9), gfs2_inplace_release(9), gfs2_alloc_extent(9), rgblk_free(9), gfs2_rgrp_dump(9), gfs2_adjust_reservation(9), gfs2_set_alloc_start(9), gfs2_alloc_blocks(9), __gfs2_free_blocks(9), gfs2_free_meta(9), gfs2_check_blk_type(9), gfs2_rlist_add(9), gfs2_rlist_alloc(9), gfs2_rlist_free(9)

like I said. everyone. ate and left no crumbs 💀

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ngl this page never actually says anything is dangerous or deprecated, so no scary warnings here — just know that clone-free genuinely means "not counting those unlinked-file blocks," that's the whole point of the distinction 🫶

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k bye ily, this page lives in ./fs/gfs2 and it's dated October 2026, so mark your calendar and stan a filesystem 💜🎀