Comment 0 for bug 1872757

SRU Justification

Impact: Christian Kellner reported that creating temporary files via O_TMPFILE shiftfs reports ESTALE. This can be reproduced via:

import tempfile
import os

def test():
    with tempfile.TemporaryFile() as fd:
        fd.write("data".encode('utf-8'))
        # re-open the file to get a read-only file descriptor
        return open(f"/proc/self/fd/{fd.fileno()}", "r")

def main():
   fd = test()
   fd.close()

if __name__ == "__main__":
    main()

a similar issue was reported here:
https://github.com/systemd/systemd/issues/14861

Regression Potential: Limited to shiftfs.

Test Case: Build a kernel with fix applied and run above reproducer.