ext4_move_extents(9)

💅 ext4_move_extents — like, the whole manual, but make it make sense

okay so bestie, welcome to the Kernel API Manual page for ext4_move_extents ✨ this is the function that, and I cannot stress this enough, exchanges the specified range of a file 🔥 like it's a whole swap situation and you're the main character orchestrating it. let's get into it 🫶

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🌸 SYNOPSIS 🌸

int ext4_move_extents (struct file *o_filp , struct file *d_filp , __u64
orig_blk , __u64 donor_blk , __u64 len , __u64 *moved_len );

like yes that's the whole signature, copy it exactly, do not come for me about the spacing, it's giving verbatim 👑

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🎀 ARGUMENTS 🎀

• o_filp — the struct file of the original file, aka the one we're messing with 💜
• d_filp — the struct file of the donor file, aka where the good stuff comes from 🦋
• orig_blk — start offset, in blocks, for orig ⭐
• donor_blk — start offset, in blocks, for donor 🌈
• len — the number of blocks to be moved, yes the actual amount, don't skimp 🙈
• moved_len — moved block length 👑

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✨ DESCRIPTION ✨

so here's the vibe check: this function returns 0 and sets the moved block length into moved_len if it succeeds 💖 otherwise? it returns an error value 😭 that's it, that's the whole deal, no cap.

lowkey important: it's 0 on success, error value on failure. don't be out here checking for the wrong thing bestie 💀

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🔥 SEE ALSO 🔥

• Kernel file ./fs/ext4/move_extent.c
• ext4_double_down_write_data_sem(9)
• ext4_double_up_write_data_sem(9)

like literally go read those too, they're iconic and you'll need them for the full picture 🧚

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and that's the page!! 🍓 this one's from ./fs/ext4, dated October 2026, and it goes by ext4_move_extents(9) — mwah, slay, periodt 💅👑