Error: EXDEV: cross-device link not permitted, rename

There are many question similar to my question on stack overflow. However not solved my problem.

I am getting this error on Ubuntu 18.04:

Error: EXDEV: cross-device link not permitted, rename ‘/tmp/upload_df97d265c452c510805679f968bb4c17’ -> ‘/home/haider/workspaceNode/DSC_0076.JPG’

I Tried This code

 var http = require('http');
    var formidable = require('formidable');
    var fs = require('fs');

http.createServer(function (req, res) {
  if (req.url == '/fileupload') {
    var form = new formidable.IncomingForm();
    form.parse(req, function (err, fields, files) {
      var oldpath = files.filetoupload.path;
      var newpath = '/home/haider/workspaceNode/' + files.filetoupload.name;
      fs.rename(oldpath, newpath, function (err) {
        if (err) throw err;
        res.write('File uploaded and moved!');
        res.end();
      });
 });
  } else {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
    res.write('<input type="file" name="filetoupload"><br>');
    res.write('<input type="submit">');
    res.write('</form>');
    return res.end();
  }
}).listen(8081);

JavaScript
​x
 
 var http = require('http');
    var formidable = require('formidable');
    var fs = require('fs');
​
http.createServer(function (req, res) {
  if (req.url == '/fileupload') {
    var form = new formidable.IncomingForm();
    form.parse(req, function (err, fields, files) {
      var oldpath = files.filetoupload.path;
      var newpath = '/home/haider/workspaceNode/' + files.filetoupload.name;
      fs.rename(oldpath, newpath, function (err) {
        if (err) throw err;
        res.write('File uploaded and moved!');
        res.end();
      });
 });
  } else {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
    res.write('<input type="file" name="filetoupload"><br>');
    res.write('<input type="submit">');
    res.write('</form>');
    return res.end();
  }
}).listen(8081);
​

Answer

I suppose that Node’s fs.rename cannot rename across filesystems (that is, limited to link/unlink within one filesystem).

Wherever your /home is, it’s a safe bet to suppose that /tmp is a tmpfs filesystem actually residing in memory. (You can check in the output of mount.)

So, to move a file, you have to fs.copyFile your data to the destination, then fs.unlink the original downloaded file.

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Answer