From 46957ed24f21396683cf9aff13fa0cd3086ea466 Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Fri, 19 Jun 2020 05:55:35 -0700 Subject: Fix synthetic file bugs in gofer fs. Always check if a synthetic file already exists at a location before creating a file there, and do not try to delete synthetic gofer files from the remote fs. This fixes runsc_ptrace socket tests that create/unlink synthetic, named socket files. Updates #2923. PiperOrigin-RevId: 317293648 --- pkg/sentry/fsimpl/gofer/filesystem.go | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'pkg/sentry/fsimpl/gofer') diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go index 3c467e313..21eb976cb 100644 --- a/pkg/sentry/fsimpl/gofer/filesystem.go +++ b/pkg/sentry/fsimpl/gofer/filesystem.go @@ -374,13 +374,16 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir return nil } if fs.opts.interop == InteropModeShared { - // The existence of a dentry at name would be inconclusive because the - // file it represents may have been deleted from the remote filesystem, - // so we would need to make an RPC to revalidate the dentry. Just - // attempt the file creation RPC instead. If a file does exist, the RPC - // will fail with EEXIST like we would have. If the RPC succeeds, and a - // stale dentry exists, the dentry will fail revalidation next time - // it's used. + if child := parent.children[name]; child != nil && child.isSynthetic() { + return syserror.EEXIST + } + // The existence of a non-synthetic dentry at name would be inconclusive + // because the file it represents may have been deleted from the remote + // filesystem, so we would need to make an RPC to revalidate the dentry. + // Just attempt the file creation RPC instead. If a file does exist, the + // RPC will fail with EEXIST like we would have. If the RPC succeeds, and a + // stale dentry exists, the dentry will fail revalidation next time it's + // used. return createInRemoteDir(parent, name) } if child := parent.children[name]; child != nil { @@ -518,7 +521,7 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b if child == nil { return syserror.ENOENT } - } else { + } else if child == nil || !child.isSynthetic() { err = parent.file.unlinkAt(ctx, name, flags) if err != nil { if child != nil { -- cgit v1.2.3