dutchcoders/transfer.sh · error

Cannot reset cache file

Error message

Cannot reset cache file

What it means

After spooling the body to a temp file, putHandler seeks the file back to the start (file.Seek(0, io.SeekStart)) so it can be re-read for scanning and storage. If the seek fails, the server responds with 500 and this message. A seek on a regular local file essentially only fails on real OS-level I/O problems.

Source

Thrown at server/handlers.go:660

			s.logger.Printf("%s", err.Error())
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		// queue file to disk, because s3 needs content length
		// and clamav prescan scans a file
		n, err := io.Copy(file, r.Body)
		if err != nil {
			s.logger.Printf("%s", err.Error())
			http.Error(w, err.Error(), http.StatusInternalServerError)

			return
		}

		_, err = file.Seek(0, io.SeekStart)
		if err != nil {
			s.logger.Printf("%s", err.Error())
			http.Error(w, "Cannot reset cache file", http.StatusInternalServerError)

			return
		}

		contentLength = n

		if s.performClamavPrescan {
			status, err := s.performScan(file.Name())
			if err != nil {
				s.logger.Printf("%s", err.Error())
				http.Error(w, "Could not perform prescan", http.StatusInternalServerError)
				return
			}

			if status != clamavScanStatusOK {
				s.logger.Printf("prescan positive: %s", status)
				http.Error(w, "Clamav prescan found a virus", http.StatusPreconditionFailed)
				return

View on GitHub (pinned to c37bfd9579)

Solutions

1. Check the server log for the underlying seek error printed just before the response.
2. Move the temp path to a reliable local filesystem (not NFS/FUSE or a pipe).
3. Check disk health (dmesg / SMART) if the error indicates hardware I/O failure.
4. Restart the server to clear any invalid descriptors and retry the upload.

Example fix

// before: temp dir on network storage
transfer --temp-path /mnt/nfs/tmp
// after: use local disk
transfer --temp-path /var/tmp/transfer

// Operators: ensure temp path is on a seekable local filesystem
fs := syscall.Statfs_t{}
if err := syscall.Statfs(tempPath, &fs); err != nil {
    log.Fatalf("temp path unavailable: %v", err)
}
// verify it is not NFS/FUSE where seek can be unreliable
if isNetworkFilesystem(tempPath) {
    log.Fatal("temp path must be local disk")
}

resp, err := http.Put(url, mime, body)
if err == nil && resp.StatusCode == 500 &&
    strings.Contains(readBody(resp), "Cannot reset cache file") {
    return fmt.Errorf("server temp filesystem failed seek; contact operator")
}

When it happens

Trigger: file.Seek(0, io.SeekStart) returns an error — typically an underlying I/O error on the temp filesystem (failing disk), the file descriptor being invalid/closed, or exotic filesystems where seek is unsupported.

Common situations: Failing or overloaded disks in /tmp; containers using unusual storage drivers; running the temp path on a network/pipe-like filesystem that does not support seeking.

Related errors

• Clamav prescan found a virus
• Could not encode metadata
• Could not save metadata
• Could not crypt file
• Could not retrieve file.

AI-assisted analysis of dutchcoders/transfer.sh@c37bfd9579 (2026-09-05). Data as JSON: /api/errors/2ebc96668855ac4b. Report an issue: GitHub.