From f09346578021c12069b6deb9487a1462b8d28a83 Mon Sep 17 00:00:00 2001 From: Nalin Dahyabhai Date: Thu, 21 Nov 2019 15:32:41 -0500 Subject: [PATCH 1/3] bind: don't complain about missing mountpoints When we go to unmount a tree of mounts, if one of the directories isn't there, instead of returning an error as before, log a debug message and keep going. Signed-off-by: Nalin Dahyabhai --- bind/mount.go | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/bind/mount.go b/bind/mount.go index e1ae323b9f..adde901fd1 100644 --- a/bind/mount.go +++ b/bind/mount.go @@ -264,6 +264,10 @@ func UnmountMountpoints(mountpoint string, mountpointsToRemove []string) error { mount := getMountByID(id) // check if this mountpoint is mounted if err := unix.Lstat(mount.Mountpoint, &st); err != nil { + if os.IsNotExist(err) { + logrus.Debugf("mountpoint %q is not present(?), skipping", mount.Mountpoint) + continue + } return errors.Wrapf(err, "error checking if %q is mounted", mount.Mountpoint) } if mount.Major != int(unix.Major(st.Dev)) || mount.Minor != int(unix.Minor(st.Dev)) { From c5fb681a6082b78c422eb3531667dc6d607a9355 Mon Sep 17 00:00:00 2001 From: Nalin Dahyabhai Date: Fri, 22 Nov 2019 14:22:26 -0500 Subject: [PATCH 2/3] chroot: Unmount with MNT_DETACH instead of UnmountMountpoints() Unmounting the rootfs with MNT_DETACH should unmount everything below it, so we don't need to use the more exhaustive method that our bind package uses for its bind mounts. Signed-off-by: Nalin Dahyabhai --- chroot/run.go | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/chroot/run.go b/chroot/run.go index fbccbcdb0d..76ac78d1ff 100644 --- a/chroot/run.go +++ b/chroot/run.go @@ -15,6 +15,7 @@ import ( "strings" "sync" "syscall" + "time" "unsafe" "github.com/containers/buildah/bind" @@ -1002,12 +1003,19 @@ func isDevNull(dev os.FileInfo) bool { // callback that will clean up its work. func setupChrootBindMounts(spec *specs.Spec, bundlePath string) (undoBinds func() error, err error) { var fs unix.Statfs_t - removes := []string{} undoBinds = func() error { - if err2 := bind.UnmountMountpoints(spec.Root.Path, removes); err2 != nil { - logrus.Warnf("pkg/chroot: error unmounting %q: %v", spec.Root.Path, err2) - if err == nil { - err = err2 + if err2 := unix.Unmount(spec.Root.Path, unix.MNT_DETACH); err2 != nil { + retries := 0 + for (err2 == unix.EBUSY || err2 == unix.EAGAIN) && retries < 50 { + time.Sleep(50 * time.Millisecond) + err2 = unix.Unmount(spec.Root.Path, unix.MNT_DETACH) + retries++ + } + if err2 != nil { + logrus.Warnf("pkg/chroot: error unmounting %q (retried %d times): %v", spec.Root.Path, retries, err2) + if err == nil { + err = err2 + } } } return err @@ -1096,6 +1104,7 @@ func setupChrootBindMounts(spec *specs.Spec, bundlePath string) (undoBinds func( // Add /sys/fs/selinux to the set of masked paths, to ensure that we don't have processes // attempting to interact with labeling, when they aren't allowed to do so. spec.Linux.MaskedPaths = append(spec.Linux.MaskedPaths, "/sys/fs/selinux") + // Bind mount in everything we've been asked to mount. for _, m := range spec.Mounts { // Skip anything that we just mounted. @@ -1141,13 +1150,11 @@ func setupChrootBindMounts(spec *specs.Spec, bundlePath string) (undoBinds func( if !os.IsNotExist(err) { return undoBinds, errors.Wrapf(err, "error examining %q for mounting in mount namespace", target) } - // The target isn't there yet, so create it, and make a - // note to remove it later. + // The target isn't there yet, so create it. if srcinfo.IsDir() { if err = os.MkdirAll(target, 0111); err != nil { return undoBinds, errors.Wrapf(err, "error creating mountpoint %q in mount namespace", target) } - removes = append(removes, target) } else { if err = os.MkdirAll(filepath.Dir(target), 0111); err != nil { return undoBinds, errors.Wrapf(err, "error ensuring parent of mountpoint %q (%q) is present in mount namespace", target, filepath.Dir(target)) @@ -1157,7 +1164,6 @@ func setupChrootBindMounts(spec *specs.Spec, bundlePath string) (undoBinds func( return undoBinds, errors.Wrapf(err, "error creating mountpoint %q in mount namespace", target) } file.Close() - removes = append(removes, target) } } requestFlags := bindFlags @@ -1266,7 +1272,6 @@ func setupChrootBindMounts(spec *specs.Spec, bundlePath string) (undoBinds func( if err := os.Mkdir(roEmptyDir, 0700); err != nil { return undoBinds, errors.Wrapf(err, "error creating empty directory %q", roEmptyDir) } - removes = append(removes, roEmptyDir) } // Set up any masked paths that we need to. If we're running inside of From ec1be6a51941e10b5316c911ef97c88940f7c095 Mon Sep 17 00:00:00 2001 From: Nalin Dahyabhai Date: Fri, 22 Nov 2019 14:52:25 -0500 Subject: [PATCH 3/3] overlay.bats typo: fuse-overlays should be fuse-overlayfs Signed-off-by: Nalin Dahyabhai --- tests/overlay.bats | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tests/overlay.bats b/tests/overlay.bats index 04056f6804..7cc2d0c622 100644 --- a/tests/overlay.bats +++ b/tests/overlay.bats @@ -3,14 +3,14 @@ load helpers @test "overlay specific level" { - if test \! -e /usr/bin/fuse-overlays -a "$BUILDAH_ISOLATION" = "rootless"; then + if test \! -e /usr/bin/fuse-overlayfs -a "$BUILDAH_ISOLATION" = "rootless"; then skip "BUILDAH_ISOLATION = $BUILDAH_ISOLATION" and no /usr/bin/fuse-overlayfs present fi image=alpine mkdir ${TESTDIR}/lower touch ${TESTDIR}/lower/foo -cid=$(buildah --log-level=error from -v ${TESTDIR}/lower:/lower:O --quiet --signature-policy ${TESTSDIR}/policy.json $image) + cid=$(buildah --log-level=error from -v ${TESTDIR}/lower:/lower:O --quiet --signature-policy ${TESTSDIR}/policy.json $image) # This should succeed run_buildah --log-level=error run $cid ls /lower/foo