gfs2_testbit(9)

🦋 gfs2_testbit(9) — test a bit in the bitmaps

okay so bestie, this is a page straight out of the Kernel API Manual, and it's about peeking at a single bit inside the GFS2 bitmaps. tiny function, huge responsibilities. no cap. 💅

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✨ NAME ✨

gfs2_testbit — test a bit in the bitmaps

like, literally just ✨checking one bit✨. that's the whole gig. 🎀

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🌸 SYNOPSIS 🌸

u8 gfs2_testbit (const struct gfs2_rbm *rbm , bool use_clone );

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💖 ARGUMENTS 💖

• rbm — the bit to test 🫶 this is the const struct gfs2_rbm * and yeah, it's pointing at exactly which bit we're checking, no guessing.
• use_clone — if this is true, you're testing the clone bitmap, not the official bitmap. like the understudy bitmap. the vibes-only bitmap. 🌈

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🧚 DESCRIPTION 🧚

okay so some callers — hi, gfs2_unaligned_extlen, we see you — need to test the clone bitmaps instead of the "real" bitmaps. and why? to avoid allocating recently freed blocks, that's why. 🚫🧱

it's giving "don't hand out a room that someone just checked out of, the sheets aren't even changed yet." periodt. 🔥

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👑 RETURN 👑

the two bit block state of the requested bit, returned as a u8. that's your vibe check result, bestie — go read it. 💀

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🌟 SEE ALSO 🌟

so, uh, this function rolls with a massive friend group. kernel file ./fs/gfs2/rgrp.c is where they all hang out, and here's the whole squad, no one left behind:

• gfs2_setbit(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_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)

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and that's the whole page, bestie!! 🍓 source ./fs/gfs2, dated October 2026, and the page is gfs2_testbit(9) — go forth and test those bits, mwah 💜🧚