diff options
| -rw-r--r-- | pkg/sentry/fsimpl/tmpfs/tmpfs.go | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go index e1439dddb..e2a0aac69 100644 --- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go +++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go @@ -74,6 +74,8 @@ type filesystem struct { mu sync.RWMutex `state:"nosave"` nextInoMinusOne uint64 // accessed using atomic memory operations + + root *dentry } // Name implements vfs.FilesystemType.Name. @@ -197,6 +199,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt fs.vfsfs.DecRef(ctx) return nil, nil, fmt.Errorf("invalid tmpfs root file type: %#o", rootFileType) } + fs.root = root return &fs.vfsfs, &root.vfsd, nil } @@ -208,6 +211,37 @@ func NewFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *au // Release implements vfs.FilesystemImpl.Release. func (fs *filesystem) Release(ctx context.Context) { fs.vfsfs.VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) + fs.mu.Lock() + if fs.root.inode.isDir() { + fs.root.releaseChildrenLocked(ctx) + } + fs.mu.Unlock() +} + +// releaseChildrenLocked is called on the mount point by filesystem.Release() to +// destroy all objects in the mount. It performs a depth-first walk of the +// filesystem and "unlinks" everything by decrementing link counts +// appropriately. There should be no open file descriptors when this is called, +// so each inode should only have one outstanding reference that is removed once +// its link count hits zero. +// +// Note that we do not update filesystem state precisely while tearing down (for +// instance, the child maps are ignored)--we only care to remove all remaining +// references so that every filesystem object gets destroyed. Also note that we +// do not need to trigger DecRef on the mount point itself or any child mount; +// these are taken care of by the destructor of the enclosing MountNamespace. +// +// Precondition: filesystem.mu is held. +func (d *dentry) releaseChildrenLocked(ctx context.Context) { + dir := d.inode.impl.(*directory) + for _, child := range dir.childMap { + if child.inode.isDir() { + child.releaseChildrenLocked(ctx) + child.inode.decLinksLocked(ctx) // link for child/. + dir.inode.decLinksLocked(ctx) // link for child/.. + } + child.inode.decLinksLocked(ctx) // link for child + } } // immutable |