diff options
Diffstat (limited to 'runsc/boot/fs.go')
| -rw-r--r-- | runsc/boot/fs.go | 143 |
1 files changed, 50 insertions, 93 deletions
diff --git a/runsc/boot/fs.go b/runsc/boot/fs.go index 42e011beb..ea825e571 100644 --- a/runsc/boot/fs.go +++ b/runsc/boot/fs.go @@ -103,9 +103,14 @@ func createMountNamespace(userCtx context.Context, rootCtx context.Context, spec return nil, fmt.Errorf("failed to create root mount namespace: %v", err) } - if err := setMounts(rootCtx, conf, mns, fds, mounts); err != nil { - return nil, fmt.Errorf("failed to configure mounts: %v", err) + root := mns.Root() + defer root.DecRef() + for _, m := range mounts { + if err := mountSubmount(rootCtx, conf, mns, root, fds, m, mounts); err != nil { + return nil, fmt.Errorf("mount submount: %v", err) + } } + if !fds.empty() { return nil, fmt.Errorf("not all mount points were consumed, remaining: %v", fds) } @@ -184,17 +189,6 @@ func compileMounts(spec *specs.Spec) []specs.Mount { return mounts } -// setMounts iterates over mounts and mounts them in the specified -// mount namespace. -func setMounts(ctx context.Context, conf *Config, mns *fs.MountNamespace, fds *fdDispenser, mounts []specs.Mount) error { - for _, m := range mounts { - if err := mountSubmount(ctx, conf, mns, fds, m, mounts, m.Destination); err != nil { - return err - } - } - return nil -} - // createRootMount creates the root filesystem. func createRootMount(ctx context.Context, spec *specs.Spec, conf *Config, fds *fdDispenser, mounts []specs.Mount) (*fs.Inode, error) { // First construct the filesystem from the spec.Root. @@ -207,9 +201,9 @@ func createRootMount(ctx context.Context, spec *specs.Spec, conf *Config, fds *f fd := fds.remove() log.Infof("Mounting root over 9P, ioFD: %d", fd) - hostFS := mustFindFilesystem("9p") + p9FS := mustFindFilesystem("9p") opts := p9MountOptions(fd, conf.FileAccess) - rootInode, err = hostFS.Mount(ctx, rootDevice, mf, strings.Join(opts, ",")) + rootInode, err = p9FS.Mount(ctx, rootDevice, mf, strings.Join(opts, ",")) if err != nil { return nil, fmt.Errorf("failed to generate root mount point: %v", err) } @@ -294,7 +288,11 @@ func getMountNameAndOptions(conf *Config, m specs.Mount, fds *fdDispenser) (stri return fsName, opts, useOverlay, err } -func mountSubmount(ctx context.Context, conf *Config, mns *fs.MountNamespace, fds *fdDispenser, m specs.Mount, mounts []specs.Mount, dest string) error { +// mountSubmount mounts volumes inside the container's root. Because mounts may +// be readonly, a lower ramfs overlay is added to create the mount point dir. +// Another overlay is added with tmpfs on top if Config.Overlay is true. +// 'm.Destination' must be an absolute path with '..' and symlinks resolved. +func mountSubmount(ctx context.Context, conf *Config, mns *fs.MountNamespace, root *fs.Dirent, fds *fdDispenser, m specs.Mount, mounts []specs.Mount) error { // Map mount type to filesystem name, and parse out the options that we are // capable of dealing with. fsName, opts, useOverlay, err := getMountNameAndOptions(conf, m, fds) @@ -340,60 +338,16 @@ func mountSubmount(ctx context.Context, conf *Config, mns *fs.MountNamespace, fd } } - // Create destination in case it doesn't exist. This is required, in addition - // to 'addSubmountOverlay', in case there are symlinks to create directories - // in the right location, e.g. - // mount: /var/run/secrets, may be created in '/run/secrets' if - // '/var/run' => '/var'. - if err := mkdirAll(ctx, mns, dest); err != nil { - return err - } - - root := mns.Root() - defer root.DecRef() - dirent, err := mns.FindInode(ctx, root, nil, dest, linux.MaxSymlinkTraversals) + dirent, err := mns.FindInode(ctx, root, root, m.Destination, 0 /* maxTraversals */) if err != nil { - return fmt.Errorf("failed to find mount destination %q: %v", dest, err) + return fmt.Errorf("failed to find mount destination %q: %v", m.Destination, err) } defer dirent.DecRef() if err := mns.Mount(ctx, dirent, inode); err != nil { - return fmt.Errorf("failed to mount at destination %q: %v", dest, err) + return fmt.Errorf("failed to mount at destination %q: %v", m.Destination, err) } - log.Infof("Mounted %q to %q type %s", m.Source, dest, m.Type) - return nil -} - -func mkdirAll(ctx context.Context, mns *fs.MountNamespace, path string) error { - log.Infof("mkdirAll called with path %s", path) - root := mns.Root() - defer root.DecRef() - - // Starting at the root, walk the path. - parent := root - ps := strings.Split(filepath.Clean(path), string(filepath.Separator)) - for _, pathElem := range ps { - if pathElem == "" { - // This will be case for the first and last element, if the path - // begins or ends with '/'. Note that we always treat the path as - // absolute, regardless of what the first character contains. - continue - } - d, err := mns.FindInode(ctx, root, parent, pathElem, fs.DefaultTraversalLimit) - if err == syserror.ENOENT { - // If we encounter a path that does not exist, then - // create it. - if err := parent.CreateDirectory(ctx, root, pathElem, fs.FilePermsFromMode(0755)); err != nil { - return fmt.Errorf("failed to create directory %q: %v", pathElem, err) - } - if d, err = parent.Walk(ctx, root, pathElem); err != nil { - return fmt.Errorf("walk to %q failed: %v", pathElem, err) - } - } else if err != nil { - return fmt.Errorf("failed to find inode %q: %v", pathElem, err) - } - parent = d - } + log.Infof("Mounted %q to %q type %s", m.Source, m.Destination, m.Type) return nil } @@ -437,14 +391,6 @@ func parseAndFilterOptions(opts []string, allowedKeys ...string) ([]string, erro return out, nil } -func destinations(mounts []specs.Mount, extra ...string) []string { - var ds []string - for _, m := range mounts { - ds = append(ds, m.Destination) - } - return append(ds, extra...) -} - // mountDevice returns a device string based on the fs type and target // of the mount. func mountDevice(m specs.Mount) string { @@ -544,7 +490,8 @@ func mustFindFilesystem(name string) fs.Filesystem { func addSubmountOverlay(ctx context.Context, inode *fs.Inode, submounts []string) (*fs.Inode, error) { // There is no real filesystem backing this ramfs tree, so we pass in // "nil" here. - mountTree, err := ramfs.MakeDirectoryTree(ctx, fs.NewNonCachingMountSource(nil, fs.MountSourceFlags{}), submounts) + msrc := fs.NewNonCachingMountSource(nil, fs.MountSourceFlags{}) + mountTree, err := ramfs.MakeDirectoryTree(ctx, msrc, submounts) if err != nil { return nil, fmt.Errorf("error creating mount tree: %v", err) } @@ -608,12 +555,16 @@ func setupContainerFS(procArgs *kernel.CreateProcessArgs, spec *specs.Spec, conf // namespace. mns := k.RootMountNamespace() if mns == nil { + // Setup the root container. + // Create the virtual filesystem. mns, err := createMountNamespace(ctx, rootCtx, spec, conf, goferFDs) if err != nil { return fmt.Errorf("error creating mounts: %v", err) } k.SetRootMountNamespace(mns) + + // We're done with root container. return nil } @@ -627,42 +578,48 @@ func setupContainerFS(procArgs *kernel.CreateProcessArgs, spec *specs.Spec, conf return fmt.Errorf("error creating filesystem for container: %v", err) } - // Make directories for submounts within the container. - rootDir := mns.Root() - defer rootDir.DecRef() - containerRoot := filepath.Join(ChildContainersDir, cid) - mkdirAll(ctx, mns, containerRoot) + globalRoot := mns.Root() + defer globalRoot.DecRef() - // Mount the container's root filesystem to the newly created - // mount point. - containerRootDirent, err := mns.FindInode(ctx, rootDir, nil, containerRoot, linux.MaxSymlinkTraversals) + // Create mount point for the container's rootfs. + contDir, err := mns.FindInode(ctx, globalRoot, nil, ChildContainersDir, 0 /* TraversalLimit */) if err != nil { - return fmt.Errorf("failed to find mount destination: %q: %v", containerRoot, err) + return fmt.Errorf("couldn't find child container dir %q: %v", ChildContainersDir, err) } - if err := mns.Mount(ctx, containerRootDirent, rootInode); err != nil { - return fmt.Errorf("failed to mount at destination %q: %v", containerRoot, err) + if err := contDir.CreateDirectory(ctx, globalRoot, cid, fs.FilePermsFromMode(0755)); err != nil { + return fmt.Errorf("create directory %q: %v", cid, err) + } + containerRoot, err := contDir.Walk(ctx, globalRoot, cid) + if err != nil { + return fmt.Errorf("walk to %q failed: %v", cid, err) + } + defer containerRoot.DecRef() + + // Mount the container's root filesystem to the newly created mount point. + if err := mns.Mount(ctx, containerRoot, rootInode); err != nil { + return fmt.Errorf("mount container root: %v", err) } - containerRootDirent.DecRef() // We have to re-walk to the dirent to find the mounted // directory. The old dirent is invalid at this point. - containerRootDirent, err = mns.FindInode(ctx, rootDir, nil, containerRoot, linux.MaxSymlinkTraversals) + containerRoot, err = contDir.Walk(ctx, globalRoot, cid) if err != nil { - return fmt.Errorf("failed to find mount destination2: %q: %v", containerRoot, err) + return fmt.Errorf("find container mount point %q: %v", cid, err) } - log.Infof("Mounted child's root fs to %q", containerRoot) + + log.Infof("Mounted child's root fs to %q", filepath.Join(ChildContainersDir, cid)) // Mount all submounts. mounts := compileMounts(spec) for _, m := range mounts { - dest := filepath.Join(containerRoot, m.Destination) - if err := mountSubmount(rootCtx, conf, k.RootMountNamespace(), fds, m, mounts, dest); err != nil { + if err := mountSubmount(rootCtx, conf, k.RootMountNamespace(), containerRoot, fds, m, mounts); err != nil { + containerRoot.DecRef() return fmt.Errorf("error mounting filesystem for container: %v", err) } } // Set the procArgs root directory. - procArgs.Root = containerRootDirent + procArgs.Root = containerRoot return nil } @@ -686,7 +643,7 @@ func destroyContainerFS(ctx context.Context, cid string, k *kernel.Kernel) error mnsRoot := mns.Root() defer mnsRoot.DecRef() containerRoot := path.Join(ChildContainersDir, cid) - containerRootDirent, err := mns.FindInode(ctx, mnsRoot, nil, containerRoot, linux.MaxSymlinkTraversals) + containerRootDirent, err := mns.FindInode(ctx, mnsRoot, nil, containerRoot, 0 /* maxTraversals */) if err == syserror.ENOENT { // Container must have been destroyed already. That's fine. return nil @@ -720,7 +677,7 @@ func destroyContainerFS(ctx context.Context, cid string, k *kernel.Kernel) error // Get a reference to the parent directory and remove the root // container directory. - containersDirDirent, err := mns.FindInode(ctx, mnsRoot, nil, ChildContainersDir, linux.MaxSymlinkTraversals) + containersDirDirent, err := mns.FindInode(ctx, mnsRoot, nil, ChildContainersDir, 0 /* maxTraversals */) if err != nil { return fmt.Errorf("error finding containers directory %q: %v", ChildContainersDir, err) } |