STRUCT NILFS_MDT_INFO(9)

✨ struct nilfs_mdt_info(9) ✨

okay so bestie, welcome to the Kernel API Manual 💖 this one's all about struct nilfs_mdt_info and tbh it's giving "backstage pass to the meta data files" energy. it's the on-memory private data of meta data files — like, the little private stash of info that meta data files keep in memory. no cap. 🎀

🌸 NAME 🌸

struct nilfs_mdt_info — on-memory private data of meta data files 💅

✨ SYNOPSIS ✨

struct nilfs_mdt_info {
    struct rw_semaphore     mi_sem;
    struct blockgroup_lock *mi_bgl;
    unsigned int            mi_entry_size;
    unsigned int            mi_first_entry_offset;
    unsigned long           mi_entries_per_block;
    struct nilfs_palloc_cache *mi_palloc_cache;
    struct nilfs_shadow_map *mi_shadow;
    unsigned long           mi_blocks_per_group;
    unsigned long           mi_blocks_per_desc_block;
 };

🦋 Members 🦋

so here's the whole cast, member by member, and yes they all ate 🔥

• mi_sem — a reader/writer semaphore for meta data operations. it's the vibe-check bouncer for reading and writing, periodt.
• mi_bgl — per-blockgroup locking. locked per blockgroup, iykyk 🔒
• mi_entry_size — the size of an entry.
• mi_first_entry_offset — the offset to the first entry. where the entries start, literally.
• mi_entries_per_block — the number of entries in a block.
• mi_palloc_cache — the persistent object allocator cache. it's the cache for the palloc, iconic.
• mi_shadow — the shadow of bmap and page caches. spooky little shadow 🌚
• mi_blocks_per_group — the number of blocks in a group.
• mi_blocks_per_desc_block — the number of blocks per descriptor block.

💜 SEE ALSO 💜

• Kernel file ./fs/nilfs2/mdt.h
• struct nilfs_shadow_map(9)

okay that's the whole page, bestie — go be a main character with your meta data structs 🌈👑

sign-off time: this little gem lives in ./fs/nilfs2, dated October 2026, and it's the struct nilfs_mdt_info(9) page of the Kernel API Manual. mwah 💋🫶