ioctl_fs(2)

ioctl_fs 💅

okay bestie, welcome to ioctl_fs(2) — the little corner of the System Calls Manual where the filesystem does its ~thing~. no cap, it's literally just "filesystem operations" and that's the whole NAME vibe ✨

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🌸 LIBRARY

Standard C library (libc, -lc) 🫶

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✨ SYNOPSIS

#include <linux/fs.h>  /* Definition of op constants */
#include <sys/ioctl.h>

int ioctl(int fd, unsigned long op, ...);

so you pull in <linux/fs.h> for the op constants (the comment fr says "Definition of op constants" 💖), plus <sys/ioctl.h>, and then you're calling ioctl with your file descriptor fd, that unsigned long op, and the ... does whatever it wants, iykyk.

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🦋 DESCRIPTION

The following op values are available. 👑

🎀 Share some of the data of one file with another file

• FICLONE(2const)
• FICLONERANGE(2const)
• FIDEDUPERANGE(2const)

it's giving ✨sharing is caring✨ — you're passing around some of the data of one file to another file. iconic behavior honestly.

🍓 Operations for inode flags

• FS_IOC_GETFLAGS(2const)
• FS_IOC_SETFLAGS(2const)

the inode flags girlies ~get~ and ~set~, main character energy 🎀

🌈 Get or set a filesystem label

• FS_IOC_GETFSLABEL(2const)
• FS_IOC_SETFSLABEL(2const)

naming your filesystem? slay. reading its name back? also slay. 💜

⭐ Get and/or clear page flags

• PAGEMAP_SCAN(2const)

peeking at page flags and/or clearing them — multi-tasking queen 👑

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💀 RETURN VALUE

On success, a nonnegative value is returned. 🫶

On error, -1 is returned, and errno is set to indicate the error. (so like, always check errno, bestie, don't just rawdog the return value 😭)

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👑 STANDARDS

Linux. that's it, that's the standard. periodt. 💅

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🔥 SEE ALSO

• ioctl(2)

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okay that's the whole page, you ate it up fr fr 🧚✨ this was Linux man-pages 6.20, dated 2025-05-17, and yes, ioctl_fs(2) really is the whole name up at the top. go forth and ioctl responsibly, my love 🫶💖🌈