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Add note about filesystems to fs::rename #25128

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May 27, 2015
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Add note about filesystems to fs::rename #25128

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2 changes: 2 additions & 0 deletions src/libstd/fs.rs
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Expand Up @@ -844,6 +844,8 @@ pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {

/// Rename a file or directory to a new name.
///
/// This will not work if the new name is on a different mount point.
///
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Technically, on linux, this will not work across mount points even if the filesystems are the same.

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@Stebalien by "filesystems are the same", is ext4 an example of a filesystem?

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Filesystem as used in this comment (i.e. partition?)

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In that you can have multiple mount points in the same partition?

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I believe that depends on the filesystem. The trivial example is bind mount which lets you mount a directory:

mkdir /path/to/a
mkdir /path/to/b
mount -o bind /path/to/a /path/to/b

These both have the same filesystem (the directory /path/to/a) but different mount points. See the EXDEV comment in man 2 rename (on linux).

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Yeah, filesystem is rather ambiguous. Maybe @steveklabnik should simply say mount point?

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In this case, filesystem is incorrect on linux (both interpretations) HOWEVER, on reading the windows spec, I get the impression that you can rename files between mount points (you can mount drives in folders: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365733%28v=vs.85%29.aspx) as long as they refer to the same underlying filesystem (partition).

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wow, impressive :)

/// # Errors
///
/// This function will return an error if the provided `from` doesn't exist, if
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