Fix an issue where copyup could fail with ENOENT

This one is rather bizarre because it triggers only on some
systems. I've included a CI test, for example, but I'm 99% sure
we use images in CI that have volumes over empty directories, and
the earlier patch to change copy-up implementation passed CI
without complaint.

I can reproduce this on a stock F33 VM, but that's the only place
I have been able to see it.

Regardless, the issue: under certain as-yet-unidentified
environmental conditions, the copier.Get method will return an
ENOENT attempting to stream a directory that is empty. Work
around this by avoiding the copy altogether in this case.

Signed-off-by: Matthew Heon <mheon@redhat.com>
This commit is contained in:
Matthew Heon
2021-02-15 11:58:24 -05:00
parent 6639b218a2
commit 759fc93343
2 changed files with 23 additions and 0 deletions

View File

@ -1617,6 +1617,17 @@ func (c *Container) mountNamedVolume(v *ContainerNamedVolume, mountpoint string)
if !srcStat.IsDir() {
return vol, nil
}
// Read contents, do not bother continuing if it's empty. Fixes
// a bizarre issue where something copier.Get will ENOENT on
// empty directories and sometimes it will not.
// RHBZ#1928643
srcContents, err := ioutil.ReadDir(srcDir)
if err != nil {
return nil, errors.Wrapf(err, "error reading contents of source directory for copy up into volume %s", vol.Name())
}
if len(srcContents) == 0 {
return vol, nil
}
// Buildah Copier accepts a reader, so we'll need a pipe.
reader, writer := io.Pipe()

View File

@ -322,6 +322,18 @@ RUN sh -c "cd /etc/apk && ln -s ../../testfile"`
Expect(outputSession.OutputToString()).To(Equal(baselineOutput))
})
It("podman named volume copyup empty directory", func() {
baselineSession := podmanTest.Podman([]string{"run", "--rm", "-t", "-i", ALPINE, "ls", "/srv"})
baselineSession.WaitWithDefaultTimeout()
Expect(baselineSession.ExitCode()).To(Equal(0))
baselineOutput := baselineSession.OutputToString()
outputSession := podmanTest.Podman([]string{"run", "-t", "-i", "-v", "/srv", ALPINE, "ls", "/srv"})
outputSession.WaitWithDefaultTimeout()
Expect(outputSession.ExitCode()).To(Equal(0))
Expect(outputSession.OutputToString()).To(Equal(baselineOutput))
})
It("podman read-only tmpfs conflict with volume", func() {
session := podmanTest.Podman([]string{"run", "--rm", "-t", "-i", "--read-only", "-v", "tmp_volume:" + dest, ALPINE, "touch", dest + "/a"})
session.WaitWithDefaultTimeout()