STRUCT CEPH_SUBVOLUME_METRIC_ENTRY_WIRE(9)

🌸 NAME 🌸

okay so bestie, welcome to the Kernel API Manual entry for struct ceph_subvolume_metric_entry_wire — it’s literally the on-wire format sent to MDS. lowkey important, highkey a struct that has to behave. 💅

✨ SYNOPSIS ✨

struct ceph_subvolume_metric_entry_wire {
    __le64 subvolume_id;
    __le32 read_ops;
    __le32 write_ops;
    __le64 read_bytes;
    __le64 write_bytes;
    __le64 read_latency_us;
    __le64 write_latency_us;
    __le64 time_stamp;
};

🎀 Members 🎀

• subvolume_id — the subvolume identifier. it’s literally the name tag for the subvolume, and we stan. 💖
• read_ops — read operation count. it’s a 32-bit value, clamped from the 64-bit internal count. so yes, it gets squished down, no cap. 🫶
• write_ops — write operation count, also 32-bit and clamped from the 64-bit internal count. same squish, different ops. 💅
• read_bytes — total bytes read. all the read bytes, accounted for. 📚
• write_bytes — total bytes written. all the write bytes, periodt. ✍️
• read_latency_us — cumulative read latency in microseconds. it’s giving “how long did reads take overall” energy. ⏱️
• write_latency_us — cumulative write latency in microseconds. same latency vibe, but for writes. 🕰️
• time_stamp — collection timestamp. important caveat: it’s currently unused, set to 0. so don’t expect it to be doing main character stuff rn. 🙈

🦋 Description 🦋

The wire format must match C++ AggregatedIOMetrics struct in MDS. that’s the rule, bestie — this struct and that C++ struct have to line up. no cap, it’s literally the whole point. 👑

🌈 SEE ALSO 🌈

• Kernel file ./fs/ceph/metric.h

mwah 💋 this cutie came from source/version ./fs/ceph, dated October 2026, and it’s filed under struct ceph...c_entry_wire(9). slay. ✨