STRUCT LIVEUPDATE_FILE_OPS(9)

💅 struct liveupdate_file_ops(9) — Kernel API Manual, bestie edition 🎀

okay so this is a page from the Kernel API Manual and it's literally all about struct liveupdate_file_ops — the callback lineup for live-updatable files. yes. files that survive a live update. main character energy fr. ✨

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🌸 NAME 🌸

struct liveupdate_file_ops — the callbacks for live-updatable files, like, the whole friend group of function pointers that make a file live-update-safe 🫶

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⭐ SYNOPSIS ⭐

struct liveupdate_file_ops {
    bool (*can_preserve)(struct liveupdate_file_handler *handler, struct
file *file);
    int (*preserve)(struct liveupdate_file_op_args *args);
    void (*unpreserve)(struct liveupdate_file_op_args *args);
    int (*freeze)(struct liveupdate_file_op_args *args);
    void (*unfreeze)(struct liveupdate_file_op_args *args);
    int (*retrieve)(struct liveupdate_file_op_args *args);
    bool (*can_finish)(struct liveupdate_file_op_args *args);
    void (*finish)(struct liveupdate_file_op_args *args);
    unsigned long (*get_id)(struct file *file);
    struct module *owner;
};

like look at her. ten members. every single one accounted for. no skips, no cuts, we stan a complete struct 💜

🦋 Members 🦋

• can_preserve — Required. ngl this is the lightweight vibe check: is this handler even compatible with the file it's being handed? quick peek, no commitment 💅
• preserve — Required. this is the one that actually does the state-saving for the file. the real work. iconic.
• unpreserve — Required. cleans up whatever preserve allocated — the "you left your jacket at my place" of callbacks 🙈
• freeze — Optional. final actions, right before the kernel transition. the last-minute "wait wait wait" before the door closes 🔥
• unfreeze — Optional. undoes the freeze operations. ctrl+z but for kernels 😭
• retrieve — Required. restores the file in the new kernel. fresh kernel, same file, slay ✨
• can_finish — Optional. checks whether this FD can finish, i.e. all the restoration pre-requirements for this FD are satisfied. it gets called prior to finish, so that the finish calls can succeed for all the resources in the session. group project energy, but make it correct 🫶
• finish — Required. final cleanup in the new kernel. last one out, turn off the lights 💀
• get_id — Optional. returns a unique identifier for the file. everybody needs their own little name tag 🎀
• owner — module reference. that's it. that's the whole description, but honestly? valid.

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👑 Description 👑

All operations (except can_preserve) receive a pointer to a

⚠️ bestie heads up, this description genuinely just stops there. it cuts off at "a" in the source. i'm not gonna invent the rest of the sentence for you — that would be lying, and we don't lie about kernel internals. the page lowkey ate and then dipped mid-sentence 😭

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💖 SEE ALSO 💖

• Kernel file ./include/linux/liveupdate.h struct
• liveupdate_file_op_args(9)
• struct liveupdate_file_handler(9)
• struct liveupdate_flb_op_args(9)
• struct liveupdate_flb_ops(9)
• struct liveupdate_flb(9)

go read those too, they're all in the same little friend circle 🌈

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and that's the whole page, bestie!! 🍓 this one lives at ./include/linux, dated October 2026, and it's filed under struct liveupdate_file_ops(9) — so like, cite her properly if you quote her 💅 periodt. 🧚