nilfs_const...sync_segment(9)

🦋 nilfs_construct_dsync_segment 🦋

okay so bestie, welcome to the Kernel API Manual ✨ this one's about NILFS2 doing a little data-only segment glow-up, and honestly? it's giving very specific but very slay. let's get into it 💅

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🎀 NAME 🎀

nilfs_construct_dsync_segment — construct a data-only logical segment 🌸

like, just the data. metadata stays home. she's a data-only queen. periodt.

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✨ SYNOPSIS ✨

int nilfs_construct_dsync_segment (struct super_block *sb , struct inode
*inode , loff_t start , loff_t end );

four args, one int back, no cap 🫶

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💖 ARGUMENTS 💖

• sb — the super block, bestie. the big one. the main character of the filesystem.
• inode — the inode whose data blocks should be written out ✍️ (yes, her data blocks specifically)
• start — start byte offset, lowkey where the party begins 🎉
• end — end byte offset, and heads up it's inclusive 👑 so she's in the range too, don't do her dirty

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🔥 RETURN 🔥

0 on success 💚 — slay, we love a clean return.

or, if things go sideways, one of these negative error codes (yes they're negative, that's the whole vibe check):

• -EIO — I/O error (including metadata corruption 😭). it's giving "the disk said no".
• -ENOMEM — insufficient memory available 💀 not enough RAM for the girl
• -ENOSPC — no space left on device (only in a panic state 🙈 like, only then, fr fr)
• -ERESTARTSYS — interrupted ✋ rude but it happens
• -EROFS — read only filesystem 🧊 she's frozen, nobody's writing anything

bestie please note: -ENOSPC is genuinely documented as happening only in a panic state, so don't go blaming her for regular out-of-space drama, iykyk 💅

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🌈 SEE ALSO 🌈

Kernel file ./fs/nilfs2/segment.c — go read her, she's iconic 📖✨

and the whole friend group:

• nilfs_transaction_begin(9)
• nilfs_transaction_commit(9)
• nilfs_segctor_reset_segment_buffer(9)
• nilfs_segctor_zeropad_segsum(9)
• nilfs_write_root_mdt_inode(9)
• nilfs_free_segments(9)
• nilfs_segctor_begin_construction(9)
• nilfs_prepare_write_logs(9)
• nilfs_segctor_start_timer(9)
• nilfs_construct_segment(9)
• nilfs_segctor_accept(9)
• nilfs_segctor_notify(9)
• nilfs_segctor_construct(9)
• nilfs_log_write_required(9)
• nilfs_segctor_thread(9)
• nilfs_segctor_destroy(9)
• nilfs_attach_log_writer(9)
• nilfs_detach_log_writer(9)

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and that's the whole page bestie 🫶 sourced straight from ./fs/nilfs2, dated October 2026, filed under nilfs_const...sync_segment(9) — mwah 💋 go write some data-only segments, you got this 🦋⭐