Error: Bad address (os error 14) when trying to unmount filesystem

[0x6D70]

The code below fails with the error Error: Bad address (os error 14)

let data_vec = vec![0_u8; 64 * 1024 * 1024];
let mut disk = Cursor::new(data_vec);

format_volume(&mut disk, FormatVolumeOptions::new().fat_type(fatfs::FatType::Fat32))?;

let fs = fatfs::FileSystem::new(disk, fatfs::FsOptions::new())?;

fs.unmount()?;

Is there an issue with my code or the library?

[rafalh]

What version are you using? I tried it with version 0.3.6 and it doesn't fail for me. With master branch it fails to compile.

[0x6D70]

Thanks with 0.3.6 it seems to work now.
But how am I supposed to read the data_vec afterwards? @rafalh

let data_vec = vec![0_u8; 64 * 1024 * 1024];
let mut disk = Cursor::new(data_vec);

format_volume(&mut disk, FormatVolumeOptions::new().fat_type(fatfs::FatType::Fat32))?;

let fs = fatfs::FileSystem::new(disk, fatfs::FsOptions::new())?;

fs.unmount()?;

fs::write(diskname, data_vec)?;  // ERROR: value used after move !!!

[rafalh]

Currently it is not possible to get back the inner disk object from FileSystem when unmounting (issue #34).
But if what you want to achieve is to write a filesystem image to a local file you can pass std::fs::File object directly to FileSystem::new instead of using Cursor with in-memory vector.

Edit: More generic approach would be to borrow Vec/Cursor instead of passing ownership. It is important to make sure passed type implements Read+Write+Seek. Fortunately Rust std lib helps here because &Read implements Read etc. Following code should work (I pass &mut disk instead of disk to FileSystem::new so it is borrowed and can still be used after fs object is destroyed):

    let data_vec = vec![0_u8; 64 * 1024 * 1024];
    let mut disk = Cursor::new(data_vec);

    format_volume(&mut disk, FormatVolumeOptions::new().fat_type(fatfs::FatType::Fat32))?;

    let fs = fatfs::FileSystem::new(&mut disk, fatfs::FsOptions::new())?;

    fs.unmount()?;
    let data_vec = disk.into_inner();
    fs::write(diskname, data_vec)?;