diff options
Diffstat (limited to 'pkg/sentry/fs/file_overlay.go')
| -rw-r--r-- | pkg/sentry/fs/file_overlay.go | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go index 4efe85832..e1f02f0f4 100644 --- a/pkg/sentry/fs/file_overlay.go +++ b/pkg/sentry/fs/file_overlay.go @@ -339,6 +339,32 @@ func (*overlayFileOperations) ConfigureMMap(ctx context.Context, file *File, opt return nil } +// UnstableAttr implements fs.FileOperations.UnstableAttr. +func (f *overlayFileOperations) UnstableAttr(ctx context.Context, file *File) (UnstableAttr, error) { + // Hot path. Avoid defers. + f.upperMu.Lock() + if f.upper != nil { + attr, err := f.upper.UnstableAttr(ctx) + f.upperMu.Unlock() + return attr, err + } + f.upperMu.Unlock() + + // It's possible that copy-up has occurred, but we haven't opened a upper + // file yet. If this is the case, just use the upper inode's UnstableAttr + // rather than opening a file. + o := file.Dirent.Inode.overlay + o.copyMu.RLock() + if o.upper != nil { + attr, err := o.upper.UnstableAttr(ctx) + o.copyMu.RUnlock() + return attr, err + } + o.copyMu.RUnlock() + + return f.lower.UnstableAttr(ctx) +} + // Ioctl implements fs.FileOperations.Ioctl and always returns ENOTTY. func (*overlayFileOperations) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { return 0, syserror.ENOTTY |