gfs2_reserv...k_and_update(9)

💅 gfs2_reservation_check_and_update — kernel API manual, bestie ✨

okay so real talk, this one lives in the Kernel API Manual, and the page header is literally gfs2_reserv...k_and_update(9) (yes the header truncates it, that's just how it's printed, don't come for me 🫶). The full-grown function name is gfs2_reservation_check_and_update, and we're about to get into it.

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🌸 NAME 🌸

gfs2_reservation_check_and_update — check for reservations during block alloc 💫

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🎀 SYNOPSIS 🎀

int gfs2_reservation_check_and_update (struct gfs2_rbm *rbm , struct gfs2_blkreserv *rs , u32 minext , struct gfs2_extent *maxext );

like, four args, one int coming back, it's giving function signature realness 👑

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🦋 ARGUMENTS 🦋

• rbm — the current position in the resource group 📍 this is where we're standing rn
• rs — our own reservation 🫶 yeah, ours, main character reservation energy
• minext — the minimum extent length 📏 the smallest we're willing to accept, no lowballing
• maxext — a pointer to the maximum extent structure 🔥 pointer bestie, so it's pointing at the max extent struct

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✨ DESCRIPTION ✨

so basically 💅 this function checks the current position in the rgrp to see whether there is a reservation covering this block. that's the whole vibe check.

if there is not one? then this function is a no-op. literally nothing happens, iconique, we move on with our lives 😌

but if there is one? then the position gets moved to the end of the contiguous reservation(s), so that we are pointing at the first non-reserved block. like sliding past the whole reserved block party until we hit the first block that isn't on the list 🎉

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⭐ RETURN ⭐

• 0 — if no reservation 🙈
• 1 — if rbm has changed 👀 (she moved, she's different now)
• otherwise — an error 💀 (not me getting a random error value, but okay)

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🔥 SEE ALSO 🔥

kernel file ./fs/gfs2/rgrp.c — home base 🏠 — plus this absolutely stacked friend group of functions, all (9), all iconic, all in the original order:

• 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)
• rgd_free(9)
• rg_mblk_search(9)
• gfs2_next_unreserved_block(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 that's 49 functions, we are obsessed with the cross-referencing 🌈

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and that's the whole page bestie, hope it slayed for you 💖

source path is ./fs/gfs2, dated October 2026 — mwah, catch you in the next manpage 🎀🦋✨