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Fix suspicious "overlayfs missing workdir or upperdir" #59

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merged 1 commit into from
Nov 20, 2025
Merged

Fix suspicious "overlayfs missing workdir or upperdir" #59

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20 changes: 12 additions & 8 deletions internal/shim/task/mount.go
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Original file line number Diff line number Diff line change
Expand Up @@ -89,9 +89,6 @@ func transformMounts(ctx context.Context, vmi vm.Instance, id string, ms []*type
udi = -1
)
for i, opt := range m.Options {
if strings.Contains(opt, "{{") {
continue
}
if strings.HasPrefix(opt, "upperdir=") {
udi = i
} else if strings.HasPrefix(opt, "workdir=") {
Expand All @@ -100,11 +97,18 @@ func transformMounts(ctx context.Context, vmi vm.Instance, id string, ms []*type
// TODO: Handle virtio for lowers?
}
if wdi > -1 && udi > -1 {
// Having the upper as virtiofs may return invalid argument, avoid
// transforming and attempt to perform the mounts on the host if
// supported.
return nil, fmt.Errorf("cannot use virtiofs for upper dir in overlay: %w", errdefs.ErrNotImplemented)
} else if wdi == -1 || udi == -1 {
//
// If any upperdir or workdir isn't transformed, they both
// should fall back to virtiofs passthroughfs. But...
//
if !strings.Contains(m.Options[wdi], "{{") ||
!strings.Contains(m.Options[udi], "{{") {
// Having the upper as virtiofs may return invalid argument, avoid
// transforming and attempt to perform the mounts on the host if
// supported.
return nil, fmt.Errorf("cannot use virtiofs for upper dir in overlay: %w", errdefs.ErrNotImplemented)
}
} else {
log.G(ctx).WithField("options", m.Options).Warnf("overlayfs missing workdir or upperdir")
}

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