VN_ISDISK(9)

💖 VN_ISDISK(9) 💖

okay so bestie, welcome to the Kernel Developer's Manual — section 9, kernel-adjacent girlies only 🫶. today we're learning about a lil function called vn_isdisk, and no cap, it's literally just asking "hey… is this thing a disk?" 🔥

✨ NAME ✨

vn_isdisk — the vibe check that tells you if a vnode is actually a disk 💅

🌸 SYNOPSIS 🌸

#include <sys/param.h>
#include <sys/vnode.h>

int
vn_isdisk(struct vnode *vp, int *errp);

like, include both headers, don't skip the second one, it's giving "necessary" 💀

🦋 DESCRIPTION 🦋

so vn_isdisk() checks whether vp represents a disk. that's the whole job. main character energy, honestly 👑

but here's the tea — for vp to actually count as a disk, all three of these gotta be true, no exceptions:

1. it has to be a character device
2. v_rdev has to be valid
3. the cdevsw entry's flags have to have D_DISK set

miss one and it's not a disk, periodt. 🙈

the arguments, bestie 🎀

• vp — the vnode you're checking. the one on trial, fr fr.
• errp — an integer pointer, and if the call fails, that's where the error number gets stored. it's the lil receipt of what went wrong 😭

⭐ RETURN VALUES ⭐

• if the vnode is a disk → 1 is returned. slay 💅✨
• otherwise → 0 is returned, and errp will contain the error number.

that's it. binary. iconic.

👑 AUTHORS 👑

this manual page was written by Chad David <davidc@acns.ab.ca>. king behavior, we love a credited author 🫶

ok that's the whole page, nothing skipped, every flag and fact intact 💜 go forth and check ur disks, bestie.

this came to you from the Debian edition of the manual, dated July 9, 2001 — yes she's vintage, she's still serving 🌈✨ bye pookie 🎀