VOP_INOTIFY(9)

💅 VOP_INOTIFY(9) — kernel dev manual, but make it cute

okay bestie, welcome to VOP_INOTIFY(9) from the Kernel Developer's Manual ✨ this is your vnode inotify interface, and yes it's as niche as it sounds, but we're gonna get through it together 🫶

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🌸 NAME 🌸

VOP_INOTIFY — vnode inotify interface. literally the whole vibe of this page, no cap 💖

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✨ SYNOPSIS ✨

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

int
VOP_INOTIFY(struct, vnode, *vp, struct, vnode, *dvp, struct,
    componentname, *cnp, int, event, uint32_t, cookie);

int
VOP_INOTIFY_ADD_WATCH(struct, vnode, *vp, struct, inotify_softc, *sc,
    uint32_t, mask, uint32_t, *wdp, struct, thread, *td);

like, copy these exactly, bestie, don't get creative with the parameter lists 🙈

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🦋 DESCRIPTION 🦋

so the VOP_INOTIFY() operation is the one that goes and tells the inotify(2) subsystem that a file system event just happened on a vnode 👀 it's giving "hey girl, something went down over here."

the dvp and cnp arguments are optional — they're only there so the operation can grab a file name for the event 🎀 if you leave them out, the inotify subsystem will fall back to the file name cache to find a name for the vnode, but heads up, that path is more expensive 💸 so if you can pass them, pass them, iykyk.

then there's VOP_INOTIFY_ADD_WATCH(), which is for internal use by the inotify subsystem to add a watch to a vnode 🧚 it's not really your main character, it's the sidekick doing the quiet work. respectfully.

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👑 LOCKS 👑

lock rules, everyone's favorite part 💀 so:

• VOP_INOTIFY() does not assume any particular vnode lock state. free spirit. no lock dress code ✨
• VOP_INOTIFY_ADD_WATCH() should be called with the vnode locked 🔒 periodt.

bestie do NOT forget the lock on that second one, it is literally the one rule they wrote down for it 😭

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🌈 RETURN VALUES 🌈

zero 0 is returned on success 🎉 (slay). otherwise, an error code is returned, and you get to go figure out what went wrong bestie, good luck 😭

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💜 SEE ALSO 💜

• inotify(2)
• vnode(9)

go read those too, they're the lore 💅

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and that's the whole page, bestie 🌟 from the Kernel Developer's Manual, this one's from Debian, dated May 27, 2025 — so it's fresh-ish, and yes the footer says it's from the VOP_INOTIFY(9) page itself. now go add some watches, but lock that vnode first, mwah 💖🎀🦋