rustfs/rustfs · error · std::io::Error

UnexpectedEof

UnexpectedEof

Error message

Unexpected EOF

What it means

Conversion pair in rustfs-filemeta's Error type: any std::io::Error of kind UnexpectedEof maps to Error::Unexpected (and back to io UnexpectedEof with message 'Unexpected EOF'). It surfaces whenever a metadata (xl.meta) read ends before the expected number of bytes — the file/stream is shorter than the header or stat size claims.

Source

Thrown at crates/filemeta/src/error.rs:142

            Error::UuidParse(s) => Error::UuidParse(s.clone()),
            Error::Unexpected => Error::Unexpected,
        }
    }
}

impl From<std::io::Error> for Error {
    fn from(e: std::io::Error) -> Self {
        match e.kind() {
            std::io::ErrorKind::UnexpectedEof => Error::Unexpected,
            _ => Error::Io(e),
        }
    }
}

impl From<Error> for std::io::Error {
    fn from(e: Error) -> Self {
        match e {
            Error::Unexpected => std::io::Error::new(std::io::ErrorKind::UnexpectedEof, "Unexpected EOF"),
            Error::Io(e) => e,
            _ => std::io::Error::other(e.to_string()),
        }
    }
}

impl From<rmp_serde::decode::Error> for Error {
    fn from(e: rmp_serde::decode::Error) -> Self {
        Error::RmpSerdeDecode(e.to_string())
    }
}

impl From<rmp_serde::encode::Error> for Error {
    fn from(e: rmp_serde::encode::Error) -> Self {
        Error::RmpSerdeEncode(e.to_string())
    }
}

View on GitHub (pinned to 9e6e02ea09)

Solutions

1. Run a heal on the bucket/object so erasure coding rebuilds the truncated xl.meta from other shards
2. If all shards are truncated, restore the object from backup or re-upload it
3. Check disk health (SMART) on the node reporting the EOF — repeated UnexpectedEof on one drive indicates failing hardware
4. Avoid file-level copies of a live pool; snapshot or quiesce before copying

use rustfs_filemeta::error::Error;
match FileMeta::load(&buf) {
    Err(Error::Unexpected) => {
        // xl.meta shorter than expected: heal the object or restore from replicas;
        // do not retry the same read — the file on disk is truncated
    }
    other => other?,
}

When it happens

Trigger: read_xl_meta* / FileMeta::load paths read an xl.meta file whose stat size says N bytes but the read returns EOF earlier (truncated file, concurrent writer, disk fault); the io error propagates through From<io::Error> and collapses into Error::Unexpected.

Common situations: Power loss mid-write leaving a truncated xl.meta; disk sectors going bad; copying a pool with rsync while it is being written; inspecting an xl.meta partially downloaded; heal reading a damaged shard.

Related errors

• Unexpected EOF
• truncated msgpack value
• Unknown minor metadata version
• Unknown major metadata version
• {}: invalid UTF-8 header value for `{}` [rustfs_signer_heade

AI-assisted analysis of rustfs/rustfs@9e6e02ea09 (2026-08-16). Data as JSON: /api/errors/6399f313db5ba915. Report an issue: GitHub.