i_uid_update(9)

💅 i_uid_update(9) — the Kernel API Manual, bestie edition 🎀

Okay so real talk, this is a page from the Kernel API Manual and it's about one tiny little function that does one tiny little thing, and honestly? She ate. Let's get into it. ✨

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🌸 NAME 🌸

i_uid_update — update @inode's i_uid field. That's it. That's the whole job. Iconic minimalism, no notes. 💖

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🦋 SYNOPSIS 🦋

void i_uid_update (struct mnt_idmap *idmap , const struct iattr *attr ,
struct inode *inode );

Look at her. Three args, returns nothing (void), zero drama. Main character energy fr fr. 👑

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✨ ARGUMENTS ✨

• idmap — the idmap of the mount the inode was found from. Basically the little translator passport for wherever this inode is living. 🛂
• attr — the new attributes of inode. The glow-up instructions, if you will. 💅
• inode — the inode to update. The one getting the makeover. 🧚

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💜 DESCRIPTION 💜

So what does she actually do? She safely updates the inode's i_uid field, translating the vfsuid of any idmapped mount into the filesystem kuid. 🫶

That's the whole vibe: safe update, translation happens, vfsuid of an idmapped mount goes in, filesystem kuid comes out. Literally the exchange-student of kernel functions. No cap. 🔥

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🌈 SEE ALSO 🌈

Bestie, buckle up, because this list is long and every single one of these is part of the extended universe. The kernel file is ./include/linux/fs.h and here's the whole squad:

1. enum positive_aop_returns(9)
2. struct address_space(9)
3. struct file_ra_state(9)
4. struct file(9)
5. i_uid_into_vfsuid(9)
6. i_uid_needs_update(9)
7. i_gid_into_vfsgid(9)
8. i_gid_needs_update(9)
9. i_gid_update(9)
10. inode_fsuid_set(9)
11. inode_fsgid_set(9)
12. fsuidgid_has_mapping(9)
13. inode_set_ctime(9)
14. file_write_started(9)
15. file_write_not_started(9)
16. struct renamedata(9)
17. is_mgtime(9)
18. iput_if_not_last(9)
19. is_idmapped_mnt(9)
20. file_start_write(9)
21. file_end_write(9)
22. kiocb_start_write(9)
23. kiocb_end_write(9)
24. name_is_dot_dotdot(9)
25. name_contains_dotdot(9)
26. inode_dio_begin(9)
27. inode_dio_end(9)
28. generic_ci_validate_strict_name(9)

Go read them all, iykyk. 💀✨

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🎀 That's the whole page bestie, she's short and she's flawless. Sourced straight from ./include/linux, dated October 2026 — so like, future vibes only. Byeee! 💖🦋🌸