lock_4_inodes(9)

💅 lock_4_inodes(9) — like, the Kernel API Manual page, bestie 🎀

okay so this is lock_4_inodes from the Kernel API Manual and honestly? it's a little four-inode moment and i'm obsessed. let's get into it ✨

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🌸 NAME 🌸

lock_4_inodes — a wrapper for locking three UBIFS inodes.

not me clocking that the NAME line says three while the function is literally called lock_4_inodes and takes four args 💀 i'm just the messenger, that's what the page says, no cap.

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✨ SYNOPSIS ✨

void lock_4_inodes (struct inode *inode1 , struct inode *inode2 , struct
inode *inode3 , struct inode *inode4 );

returns nothing (void), takes four struct inode * pointers, and that's the whole mood 🫶

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🦋 ARGUMENTS 🦋

• inode1 — first inode 👑
• inode2 — second inode ⭐
• inode3 — third inode 🌈
• inode4 — fourth inode 💜

four inodes, four icons, all lined up 🎀

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💖 DESCRIPTION 💖

so here's the tea: this function is used for ubifs_rename, and plot twist — inode1 may be the same as inode2, whereas inode3 and inode4 may be NULL. slay, flexible friend group 💅

and ngl? there are no tricks in here to guarantee strict lock ordering. not one. zero. because VFS already did it for us on the i_mutex — it ate and left no crumbs 🔥 so this is literally just a simple wrapper function. that's it. that's the whole function. main character energy but make it minimal ✨

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👑 SEE ALSO 👑

kernel file ./fs/ubifs/dir.c plus the whole squad:

• inherit_flags(9)
• ubifs_new_inode(9)
• lock_2_inodes(9)
• unlock_2_inodes(9)
• vfs_dent_type(9)
• ubifs_check_dir_empty(9)
• unlock_4_inodes(9)

iykyk 🧚

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lowkey important reminder bestie: four inodes get locked, two of them might be the same inode, two of them might be NULL, and the ordering situation is handled by VFS on the i_mutex — not by any extra trickery in here 🙈

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and that's a wrap, gorgeous 💜 this page lives in ./fs/ubifs and it's dated October 2026 — mwah, mwah, periodt 🍓✨