VOP_CREATE(9)

💅 VOP_CREATE — the Kernel Developer's Manual, bestie edition (section 9) 🎀

okay so. welcome to the group chat where we make files. this is VOP_CREATE(9), and honestly? it's giving main character energy in the VFS world. let's go ✨

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🌸 NAME 🌸

VOP_CREATE, VOP_MKNOD, VOP_MKDIR, VOP_SYMLINK — bestie, these are the entry points that create a file, socket, fifo, device, directory or symlink. the whole "new thing appears in your filesystem" vibe, no cap. 🦋

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✨ SYNOPSIS ✨

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

int
VOP_CREATE(struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp, struct vattr *vap);

int
VOP_MKNOD(struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp, struct vattr *vap);

int
VOP_MKDIR(struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp, struct vattr *vap);

int
VOP_SYMLINK(struct vnode *dvp, struct vnode **vpp,
    struct componentname *cnp, struct vattr *vap, char *target);

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👑 DESCRIPTION 👑

so these entry points create a brand new file, socket, fifo, device, directory or symlink inside a given directory. literally birthing an inode. iconic. 🌈

the arguments, one by one, because we don't skip:

• dvp — the locked vnode of the directory. locked. do not forget. 🔒
• vpp — the address of a variable where the resulting locked vnode should be stored. that's where your new baby goes. 🍼
• cnp — the pathname component being created.
• vap — the attributes that the new object should be created with. its whole personality, basically. 💅
• target — the pathname of the target of the symlink. (symlink-only behaviour, iykyk 🔗)

and fr fr: these entry points get called after VOP_LOOKUP(9) when an object is being created. like, lookup goes first, then the creation happens. order matters, bestie. 🫶

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🔒 LOCKS 🔒

the directory, dvp, will be locked on entry and must remain locked on return. not optional. do not unlock it, do not pass go, do not collect $200. 💀

and if the call is successful? the new object will be returned locked. so it arrives locked, and it stays locked, and it's yours to deal with. 💖

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🎀 RETURN VALUES 🎀

if it slayed: the vnode for the new object is placed in *vpp and zero is returned. ✅

otherwise: an appropriate error is returned. 😭

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💀 ERRORS 💀

• [ENOSPC] — The file system is full. no room. the disk said no. 🚫
• [EDQUOT] — The user's file system space or inode quota would be exceeded. bestie you hit your limit. 🧚

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🦋 SEE ALSO 🦋

• vnode(9)
• VOP_LOOKUP(9)

go read those, they're relevant, I promise. 📚

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⭐ HISTORY ⭐

The function VOP_CREATE appeared in 4.3BSD. vintage. a classic. we stan a legacy API. 🕰️

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💜 AUTHORS 💜

This manual page was written by Doug Rabson. thank you Doug, king behavior. 👑

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and that's the whole page bestie!! it's from the Debian manual, dated July 24, 1996 — yes, 1996, ancient, retro, lowkey iconic — and it's the VOP_CREATE(9) kernel developer's page. mwah. 💖✨🎀