LLAPI_PCC_ATTACH(3)

💖 LLAPI_PCC_ATTACH 💖

okay bestie, welcome to the LLAPI_PCC_ATTACH(3) page, part of the Lustre Library Functions saga 🌸 this one's all about yeeting a file into PCC and honestly? it's giving main character energy. let's get into it 🫶

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✨ NAME ✨

llapi_pcc_attach, llapi_pcc_attach_fid, llapi_pcc_attach_fid_str — attach a file into PCC 🎀

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✨ SYNOPSIS ✨

#include <lustre/lustreapi.h>

int llapi_pcc_attach(const char *path, __u32 id,
                     enum lu_pcc_type type);

int llapi_pcc_attach_fid(const char *mntpath, const struct lu_fid *fid,
                         __u32 id, enum lu_pcc_type type);

int llapi_pcc_attach_fid_str(const char *mntpath, const char *fidstr,
                             __u32 id, enum lu_pcc_type type);

like… three besties, one mission 💅 and yes, you gotta include <lustre/lustreapi.h> first or nothing works, that's just the rules.

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✨ DESCRIPTION ✨

so the whole squad — llapi_pcc_attach(), llapi_pcc_attach_fid() and llapi_pcc_attach_fid_str() — is literally just trying to attach the file referenced by path, fid, or fidstr into a PCC backend. that's the vibe 💫

now, PCC is serving a whole group of local caches and it works in two modes, and you need to know both, no skipping 🔥:

• RW-PCC enables a read-write cache on the local SSDs of a single client. one client, living its solo era.
• RO-PCC provides a read-only cache on the local SSDs of multiple clients. group chat energy, read-only edition.

for RW-PCC, the argument id is the archive ID of the copytool agent running on this client. yes, this client specifically 👀

by default, the RO-PCC attach ID is set the same as the RW-PCC attach ID for a PCC backend if it's also used as read-only caching. so they share, cute 🥰

the attach mode is specified by the type argument, which is an enum lu_pcc_type data structure, and it contains these values:

LU_PCC_NONE
LU_PCC_READWRITE
LU_PCC_READONLY

🌈 the type values, explained 🌈

• LU_PCC_NONE — means that the file is not cached on PCC. it's giving "not invited to the cache party" 💀
• LU_PCC_READWRITE — means RW-PCC mode 🔥
• LU_PCC_READONLY — means RO-PCC mode 🦋

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✨ RETURN VALUES ✨

llapi_pcc_attach() returns 0 on success, or a negative errno value on failure. zero = slay, negative = it's not slaying 😭

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✨ ERRORS ✨

these are the little gremlins that can show up when things go sideways 🙈:

• -ENOMEM — insufficient memory to complete operation. the memory said "no 💅"
• -EFAULT — memory region is not properly mapped.
• -EINVAL — one or more invalid arguments are given.
• -EOPNOTSUPP — PCC attach operation is not supported. this one's just not available in your area, bestie.

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✨ AVAILABILITY ✨

llapi_pcc_attach(), llapi_pcc_attach_fid() and llapi_pcc_attach_fid_str() are part of the lustre(7) user application interface library since release 2.13.0 ⭐ so if you're on something older… yeah, no cap, you're out of luck.

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✨ SEE ALSO ✨

• lustreapi(7) 👑

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real talk bestie: this is the Lustre User API page, dated 2024-08-28, and it lives under the manual name LLAPI_PCC_ATTACH(3) — so that's the one to man when you need it 📖💖 now go attach those files, you absolute icon 🎀✨💅