nilfs_cpfile...kpoint_block(9)

📦 version 7.3.1, in nixpkgs unstable

✨ nilfs_cpfile_find_checkpoint_block(9) ✨

okay so bestie, welcome to the Kernel API Manual, section 9 — today's main character is nilfs_cpfile_find_checkpoint_block, and no cap, this one is literally just "go find that checkpoint block and grab it" energy 🎀

💖 NAME 💖

nilfs_cpfile_find_checkpoint_block — find and get a buffer on cpfile 🦋

like, it finds the block, it gets the buffer, it's giving errand-runner for the checkpoint file, periodt.

✨ SYNOPSIS ✨

int nilfs_cpfile_find_checkpoint_block (struct inode *cpfile , __u64
start_cno , __u64 end_cno , __u64 *cnop , struct buffer_head **bhp );

that's the whole vibe, copy it exactly, don't be weird about it 💅

🌸 ARGUMENTS 🌸

  • cpfile — the inode of cpfile 💜 like, the actual checkpoint file we're digging around in
  • start_cno — start checkpoint number, inclusive (yes bestie, it counts) ✨
  • end_cno — end checkpoint number, inclusive too, both ends are invited to the party 🎀
  • cnop — the place to store the next checkpoint number 📌 write it down, don't lose it
  • bhp — the place to store a pointer to the buffer_head struct 🫶 that's the buffer pointer handoff spot

🔥 RETURN 🔥

0 on success 🎉 — and on failure, one of these negative error codes, and yes they're all a little bit of a moment 😭:

  • -EIO — I/O error (including metadata corruption 💀). yeah, that one's rough, the metadata is corrupted, we're not okay
  • -ENOENT — no block exists in the range 🙈 literally nothing there, empty, ghost town
  • -ENOMEM — Insufficient memory available 😵‍💫 out of memory, the classic
ngl, -EIO is the dramatic one — metadata corruption is not a vibe check you want to fail ⚠️

👑 SEE ALSO 👑

Kernel file ./fs/nilfs2/cpfile.c — and the whole cpfile friend group, all iconic, all linked:

aaand that's the page bestie 💅💖 this lil gem lives at ./fs/nilfs2, dated October 2026, and it's serving kernel API manual realness from start to finish. slay, go read your checkpoints 🧚‍♀️⭐🌈

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