nilfs_mdt_find_block(9)

📦 version 7.3.1, in nixpkgs unstable

💅 nilfs_mdt_find_block — from the Kernel API Manual, bestie 🎀

Okay so grab a strawberry drink 🍓 because we're diving into nilfs_mdt_find_block(9), a real one from the kernel API manual. She's a function, she finds blocks on a metadata file, and honestly? She ate. ✨

🌸 NAME 🌸

nilfs_mdt_find_block — literally just find and get a buffer on a meta data file, that's the whole vibe 💖

✨ SYNOPSIS ✨

int nilfs_mdt_find_block (struct inode *inode , unsigned long start ,
       unsigned long end , unsigned long *blkoff , struct buffer_head **out_bh
);

No cap, that's the exact signature, don't come for me 🫶

🦋 ARGUMENTS 🦋

  • inode — the inode of the meta data file, like her whole identity ngl 👑
  • start — the start block offset, and yes it's inclusive (she's invited to the party)
  • end — the end block offset, also inclusive, she's invited too 💜
  • blkoff — the block offset
  • out_bh — the place to store a pointer to the buffer_head struct, like a lil gift bag 🎁

🔥 DESCRIPTION 🔥

So nilfs_mdt_find_block looks up an existing block in the range of [start, end] — inclusive on both ends, we been knew — and then it stores a pointer to a buffer head of that block into out_bh, and the block offset into blkoff, respectively. Two little deliveries, one call 💫

Lowkey important caveat bestie: out_bh and blkoff are substituted only when zero is returned. So like, don't go reading those outputs before a 0, that's not the moment 🙈

⭐ RETURN ⭐

0 on success — slay, iconic, we love a clean return 💅 Or one of these following negative error codes on failure, because sometimes it's just not her day 😭

  • -EIO — I/O error, including metadata corruption 💀 that's the messy one fr fr
  • -ENOENT — no block was found in the range, she looked and there was nothing there 🫠
  • -ENOMEM — insufficient memory available, the machine said "not today" 🧚

🌈 SEE ALSO 🌈

Kernel file ./fs/nilfs2/mdt.c — go read the source, iykyk 📖 and also these icons, all in the same friend group:

And that's the whole thing! 🌟 This absolute queen lives in ./fs/nilfs2, dated October 2026, and she's nilfs_mdt_find_block(9) from the Kernel API Manual — drink water, close your brackets, and go find some blocks bestie 💖🦋✨

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