STRUCT UBIFS_JHEAD(9)

✨ struct ubifs_jhead(9) ✨

okay so bestie, we're in the Kernel API Manual today and the main character is literally struct ubifs_jhead(9) — yes, that IS a struct in the kernel, and yes, it's giving "journal head" 💅

---

🎀 NAME 🎀

struct ubifs_jhead — journal head. that's it, that's the whole name. short, sweet, iconic ✨

---

🌸 SYNOPSIS 🌸

struct ubifs_jhead {
    struct ubifs_wbuf wbuf;
    struct list_head buds_list;
    unsigned int grouped:1;
    struct shash_desc *log_hash;
 };

no cap, that's the whole shape of it 🦋

---

🦋 Members 🦋

• wbuf — the head's write-buffer. that's where the writing happens, bestie 🫶
• buds_list — a list of bud LEBs that belong to this journal head. very "these are my buds and they're with me" energy 🌈
• grouped — non-zero if UBIFS groups nodes when writing to this journal head. like, it's either zero or it's not, yk? ✨
• log_hash — the log hash from the commit start node all the way up to this journal head. it's the whole journey fr 🔥

---

💜 Description 💜

⚠️ heads up bestie, and this is the important bit: the buds list is protected by the c->buds_lock. do not forget the lock. the lock is sacred. respect the lock 🔒

ngl that's the entire description, so we're not padding it out. sometimes less is more, periodt 💅

---

👑 SEE ALSO 👑

Kernel file ./fs/ubifs/ubifs.h — and then a whole squad of related structs and functions, all of them absolute legends:

• struct ubifs_old_idx(9)
• struct ubifs_scan_node(9)
• struct ubifs_scan_leb(9)
• struct ubifs_gced_idx_leb(9)
• struct ubifs_inode(9)
• struct ubifs_unclean_leb(9)
• struct ubifs_lprops(9)
• struct ubifs_lpt_lprops(9)
• struct ubifs_lp_stats(9)
• struct ubifs_cnode(9)
• struct ubifs_pnode(9)
• struct ubifs_nbranch(9)
• struct ubifs_nnode(9)
• struct ubifs_lpt_heap(9)
• struct ubifs_wbuf(9)
• struct ubifs_bud(9)
• struct ubifs_zbranch(9)
• struct ubifs_znode(9)
• struct bu_info(9)
• struct ubifs_node_range(9)
• struct ubifs_compressor(9)
• struct ubifs_budget_req(9)
• struct ubifs_orphan(9)
• struct ubifs_mount_opts(9)
• struct ubifs_budg_info(9)
• struct ubifs_stats_info(9)
• struct ubifs_info(9)
• ubifs_check_hash(9)
• ubifs_check_hmac(9)
• ubifs_branch_hash(9)
• ubifs_copy_hash(9)
• ubifs_auth_node_sz(9)

like, the whole friend group showed up to the function call 💖 the way that list just keeps going?? obsessed 😭

---

🌸 that's the whole page, bestie — slay, you made it to the end 🌸

this little baddie lives in ./fs/ubifs and the version/date on it is October 2026, filed under struct ubifs_jhead(9). go read the source, it's free real estate 🧚‍♀️🍓💜