gfs2_write_calc_reserv(9)

✨ gfs2_write_calc_reserv(9) ✨

okay so bestie, welcome to the kernel API manual 💖 this little function lives in the gfs2_write_calc_reserv(9) section and honestly? it's giving "math girlie does your homework for you" 🧮✨

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🌸 NAME 🌸

gfs2_write_calc_reserv — calculate number of blocks needed to write to a file 💅 no cap, that's literally the whole job. you hand it a file and a byte count, it tells you how many blocks you're gonna need. iconic.

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🦋 SYNOPSIS 🦋

void gfs2_write_calc_reserv (const struct gfs2_inode *ip , unsigned int len , unsigned int *data_blocks , unsigned int *ind_blocks );

it returns void btw — so it's not giving you an answer back directly 🙈 it writes the answers into the pointers you pass in. main character energy of "i don't return, i delegate" 💀

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🎀 ARGUMENTS 🎀

• ip — the file 🔥 that's your const struct gfs2_inode *, the actual file you're about to write to. it's const, so hands off, we're just looking 👀
• len — the number of bytes to be written to the file 🍓 this is the unsigned int that tells the function how much you're actually trying to shove in there
• data_blocks — returns the number of data blocks required 💖 an unsigned int * out-param, so the function drops the data-block count right into it
• ind_blocks — returns the number of indirect blocks required 🌈 also an unsigned int * out-param, this one gets the indirect-block count. yes bestie, indirect blocks are a whole vibe, they're the blocks that point at other blocks 🫶

ngl, both data_blocks and ind_blocks are returned through pointers — so make sure you're passing real, writable unsigned int storage and not some nonsense, okay? 😭 the manpage just says they "return" the counts; it doesn't say what happens if you pass garbage, so let's not find out 💀

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💜 SEE ALSO 💜

• Kernel file ./fs/gfs2/bmap.h ⭐ like, go read the source bestie, that's where the real lore lives iykyk 📖

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and that's the whole page, no notes 👑

kisses and good vibes from ./fs/gfs2, dated October 2026 — this manual page said periodt and logged off 🎀✨💅