STRUCT BLK_ZONE(9)

✨ NAME ✨

struct blk_zone — the zone descriptor for the BLKREPORTZONE ioctl 💖

So this is a page from the Kernel API Manual, bestie, and it's basically the receipts for one single zone out of a zoned block device. Iconic little struct. Let's get into it 🫶

---

🌸 SYNOPSIS 🌸

struct blk_zone {
    __u64 start;
    __u64 len;
    __u64 wp;
    __u8 type;
    __u8 cond;
    __u8 non_seq;
    __u8 reset;
    __u8 resv[4];
    __u64 capacity;
    __u8 reserved[24];
 };

No cap, that's the whole thing. Every field, every byte accounted for. 👑

---

🎀 Members 🎀

• start — where the zone starts, measured in 512 B sector units 📍
• len — how long the zone is, also in 512 B sector units 📏
• wp — the zone's write pointer location, in 512 B sector units ✍️
• type — peep enum blk_zone_type for the possible values 🏷️
• cond — peep enum blk_zone_cond for the possible values 🔍
• non_seq — flag that says the zone is using non-sequential resources (this one's for host-aware zoned block devices ONLY, iykyk) 🚩
• reset — flag that says a zone reset is recommended 👀
• resv — padding for 8B alignment 🧽
• capacity — the zone's usable capacity, in 512 B sector units 💪
• reserved — padding to 64 B so it matches the ZBC, ZAC and ZNS defined zone descriptor size 📦

---

🦋 Description 🦋

Okay so real talk: start, len, capacity and wp all use the regular 512 B sector unit, no matter what the device's logical block size is. Periodt. Don't let the block size gaslight you 💅

And the overall structure size is 64 B, which matches the ZBC, ZAC and ZNS defined zone descriptor and lets them support future additional zone information later. It's giving future-proofing, lowkey iconic 🌈

---

💜 SEE ALSO 💜

Kernel file ./include/uapi/linux/blkzoned.h and its besties: enum blk_zone_type(9), enum blk_zone_cond(9), enum blk_zone_report_flags(9), struct blk_zone_report(9), struct blk_zone_range(9) ✨

---

And that's the whole vibe check, bestie 🧚 This one's living in ./include/uapi/linux, dated October 2026, and yes — it's struct blk_zone(9) till the end 😭💖 Slay responsibly 🎀