diff options
| -rw-r--r-- | pkg/sentry/fs/file_overlay.go | 28 | ||||
| -rw-r--r-- | pkg/sentry/fs/inode_overlay.go | 13 |
2 files changed, 25 insertions, 16 deletions
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go index 9dc58d5ff..696613f3a 100644 --- a/pkg/sentry/fs/file_overlay.go +++ b/pkg/sentry/fs/file_overlay.go @@ -177,10 +177,16 @@ func (f *overlayFileOperations) Readdir(ctx context.Context, file *File, seriali // IterateDir implements DirIterator.IterateDir. func (f *overlayFileOperations) IterateDir(ctx context.Context, d *Dirent, dirCtx *DirCtx, offset int) (int, error) { o := d.Inode.overlay + o.copyMu.RLock() + defer o.copyMu.RUnlock() + return overlayIterateDirLocked(ctx, o, d, dirCtx, offset) +} +// Preconditions: o.copyMu must be locked. +func overlayIterateDirLocked(ctx context.Context, o *overlayEntry, d *Dirent, dirCtx *DirCtx, offset int) (int, error) { if !d.Inode.MountSource.CacheReaddir() { // Can't use the dirCache. Simply read the entries. - entries, err := readdirEntries(ctx, o) + entries, err := readdirEntriesLocked(ctx, o) if err != nil { return offset, err } @@ -198,15 +204,6 @@ func (f *overlayFileOperations) IterateDir(ctx context.Context, d *Dirent, dirCt } o.dirCacheMu.RUnlock() - // readdirEntries holds o.copyUpMu to ensure that copy-up does not - // occur while calculating the readdir results. - // - // However, it is possible for a copy-up to occur after the call to - // readdirEntries, but before setting o.dirCache. This is OK, since - // copy-up does not change the children in a way that would affect the - // children returned in dirCache. Copy-up only moves files/directories - // between layers in the overlay. - // // We must hold dirCacheMu around both readdirEntries and setting // o.dirCache to synchronize with dirCache invalidations done by // Create, Remove, Rename. @@ -216,7 +213,7 @@ func (f *overlayFileOperations) IterateDir(ctx context.Context, d *Dirent, dirCt // chance that a racing call managed to just set it, in which case we // can use that new value. if o.dirCache == nil { - dirCache, err := readdirEntries(ctx, o) + dirCache, err := readdirEntriesLocked(ctx, o) if err != nil { o.dirCacheMu.Unlock() return offset, err @@ -444,12 +441,11 @@ func (f *overlayFileOperations) SetFifoSize(size int64) (rv int64, err error) { return sz.SetFifoSize(size) } -// readdirEntries returns a sorted map of directory entries from the +// readdirEntriesLocked returns a sorted map of directory entries from the // upper and/or lower filesystem. -func readdirEntries(ctx context.Context, o *overlayEntry) (*SortedDentryMap, error) { - o.copyMu.RLock() - defer o.copyMu.RUnlock() - +// +// Preconditions: o.copyMu must be locked. +func readdirEntriesLocked(ctx context.Context, o *overlayEntry) (*SortedDentryMap, error) { // Assert that there is at least one upper or lower entry. if o.upper == nil && o.lower == nil { panic("invalid overlayEntry, needs at least one Inode") diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go index b16ab08ba..e97afc626 100644 --- a/pkg/sentry/fs/inode_overlay.go +++ b/pkg/sentry/fs/inode_overlay.go @@ -333,6 +333,19 @@ func overlayRemove(ctx context.Context, o *overlayEntry, parent *Dirent, child * } child.Inode.overlay.copyMu.RLock() defer child.Inode.overlay.copyMu.RUnlock() + if child.Inode.StableAttr.Type == Directory { + // RemoveDirectory requires that the directory is empty. + ser := &CollectEntriesSerializer{} + dirCtx := &DirCtx{ + Serializer: ser, + } + if _, err := overlayIterateDirLocked(ctx, child.Inode.overlay, child, dirCtx, 0); err != nil { + return err + } + if ser.Written() != 0 { + return syserror.ENOTEMPTY + } + } if child.Inode.overlay.upper != nil { if child.Inode.StableAttr.Type == Directory { if err := o.upper.InodeOperations.RemoveDirectory(ctx, o.upper, child.name); err != nil { |