LLAPI_GROUP_LOCK(3)

✨ LLAPI_GROUP_LOCK(3) ✨

okay bestie, gather round 💖 this one lives in the Lustre Library Functions corner of the manual (section 3, the library-call girlies), and it's literally just: get a group lock, put a group lock. that's the whole vibe. no cap.

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🌸 NAME 🌸

llapi_group_lock, llapi_group_unlock, llapi_group_lock64, llapi_group_unlock64 — get and put a Lustre group lock. 💅

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🎀 SYNOPSIS 🎀

#include <lustre/lustreapi.h>

int llapi_group_lock(int fd, int gid);
int llapi_group_lock64(int fd, __u64 gid);

int llapi_group_unlock(int fd, int gid);
int llapi_group_unlock64(int fd, __u64 gid);

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🦋 DESCRIPTION 🦋

so the way this works, bestie:

llapi_group_lock() and llapi_group_lock64() take a group lock on the file descriptor fd with group identifier gid (which is either an int or a __u64 type, depending on which one you call, obviously 💅).

llapi_group_unlock() and llapi_group_unlock64() release a group lock identified by group identifier gid (again, int or __u64 type) on the file descriptor fd. give it back, girl. 🫶

and now the actual tea ☕ — the group lock is a whole file lock that blocks concurrent I/O originating from descriptors that have not been locked. so if you didn't lock it, you're not doing I/O to it, periodt. 💀

but here's the slay part: multiple processes can acquire a lock by specifying the same group identifier. yes bestie, it's a group chat. everyone with the same gid gets in. 👑

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💖 RETURN VALUES 💖

llapi_group_lock(), llapi_group_lock64(), llapi_group_unlock() and llapi_group_unlock64() all return 0 on success, or a negative errno value on failure. 😭

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🔥 ERRORS 🔥

• -EBADF — fd is not a valid file descriptor. it's giving fake ID. 🙈
• -ENOTTY — fd does not describe an object suitable for this request. wrong girl, wrong function. 💀
• -EINVAL — fd is already group locked with a different group identifier. you're already in a different group chat, babe, pick one. 😤

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🌈 AVAILABILITY 🌈

llapi_group_lock(), llapi_group_unlock(), llapi_group_lock64() and llapi_group_unlock64() are all part of the lustre(7) user application interface library. iconic. ✨

timeline check, because we love an origin story:

• llapi_group_lock and llapi_group_unlock were added in release 2.7.0. OG behaviour. 👑
• llapi_group_lock64 and llapi_group_unlock64 were added in release 2.15.0. the 64-bit glow-up, we love to see it. 💅

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⭐ SEE ALSO ⭐

• lustreapi(7)

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and that's the whole page, bestie, you ate that 🍓 mwah 💜

written by the Lustre User API girlies, dated 2024-08-27 — catch you in the next manpage, ily, bye 🎀🦋✨