diff options
Diffstat (limited to 'pkg/sentry/vfs/mount.go')
| -rw-r--r-- | pkg/sentry/vfs/mount.go | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go index d39528051..31a4e5480 100644 --- a/pkg/sentry/vfs/mount.go +++ b/pkg/sentry/vfs/mount.go @@ -38,6 +38,8 @@ import ( // // Mount is analogous to Linux's struct mount. (gVisor does not distinguish // between struct mount and struct vfsmount.) +// +// +stateify savable type Mount struct { // vfs, fs, and root are immutable. References are held on fs and root. // @@ -85,6 +87,8 @@ type Mount struct { // MountNamespace methods require that a reference is held. // // MountNamespace is analogous to Linux's struct mnt_namespace. +// +// +stateify savable type MountNamespace struct { // root is the MountNamespace's root mount. root is immutable. root *Mount @@ -114,6 +118,7 @@ type MountNamespace struct { func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth.Credentials, source, fsTypeName string, opts *GetFilesystemOptions) (*MountNamespace, error) { rft := vfs.getFilesystemType(fsTypeName) if rft == nil { + ctx.Warningf("Unknown filesystem: %s", fsTypeName) return nil, syserror.ENODEV } fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, *opts) @@ -134,6 +139,23 @@ func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth return mntns, nil } +// NewDisconnectedMount returns a Mount representing fs with the given root +// (which may be nil). The new Mount is not associated with any MountNamespace +// and is not connected to any other Mounts. References are taken on fs and +// root. +func (vfs *VirtualFilesystem) NewDisconnectedMount(fs *Filesystem, root *Dentry, opts *MountOptions) (*Mount, error) { + fs.IncRef() + if root != nil { + root.IncRef() + } + return &Mount{ + vfs: vfs, + fs: fs, + root: root, + refs: 1, + }, nil +} + // MountAt creates and mounts a Filesystem configured by the given arguments. func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentials, source string, target *PathOperation, fsTypeName string, opts *MountOptions) error { rft := vfs.getFilesystemType(fsTypeName) @@ -231,9 +253,12 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti return syserror.EINVAL } vfs.mountMu.Lock() - if mntns := MountNamespaceFromContext(ctx); mntns != nil && mntns != vd.mount.ns { - vfs.mountMu.Unlock() - return syserror.EINVAL + if mntns := MountNamespaceFromContext(ctx); mntns != nil { + defer mntns.DecRef() + if mntns != vd.mount.ns { + vfs.mountMu.Unlock() + return syserror.EINVAL + } } // TODO(jamieliu): Linux special-cases umount of the caller's root, which @@ -423,7 +448,8 @@ func (mntns *MountNamespace) IncRef() { } // DecRef decrements mntns' reference count. -func (mntns *MountNamespace) DecRef(vfs *VirtualFilesystem) { +func (mntns *MountNamespace) DecRef() { + vfs := mntns.root.fs.VirtualFilesystem() if refs := atomic.AddInt64(&mntns.refs, -1); refs == 0 { vfs.mountMu.Lock() vfs.mounts.seq.BeginWrite() |