From 5042ea7e2cbdc0c04fd454583589a3b1e152f95d Mon Sep 17 00:00:00 2001 From: Jamie Liu Date: Thu, 23 Apr 2020 15:35:56 -0700 Subject: Add vfs.MkdirOptions.ForSyntheticMountpoint. PiperOrigin-RevId: 308143529 --- pkg/sentry/vfs/options.go | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'pkg/sentry/vfs/options.go') diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go index 534528ce6..022bac127 100644 --- a/pkg/sentry/vfs/options.go +++ b/pkg/sentry/vfs/options.go @@ -33,6 +33,25 @@ type GetDentryOptions struct { type MkdirOptions struct { // Mode is the file mode bits for the created directory. Mode linux.FileMode + + // If ForSyntheticMountpoint is true, FilesystemImpl.MkdirAt() may create + // the given directory in memory only (as opposed to persistent storage). + // The created directory should be able to support the creation of + // subdirectories with ForSyntheticMountpoint == true. It does not need to + // support the creation of subdirectories with ForSyntheticMountpoint == + // false, or files of other types. + // + // FilesystemImpls are permitted to ignore the ForSyntheticMountpoint + // option. + // + // The ForSyntheticMountpoint option exists because, unlike mount(2), the + // OCI Runtime Specification permits the specification of mount points that + // do not exist, under the expectation that container runtimes will create + // them. (More accurately, the OCI Runtime Specification completely fails + // to document this feature, but it's implemented by runc.) + // ForSyntheticMountpoint allows such mount points to be created even when + // the underlying persistent filesystem is immutable. + ForSyntheticMountpoint bool } // MknodOptions contains options to VirtualFilesystem.MknodAt() and -- cgit v1.2.3