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authorgVisor bot <gvisor-bot@google.com>2021-02-17 23:45:20 +0000
committergVisor bot <gvisor-bot@google.com>2021-02-17 23:45:20 +0000
commit45be62df210badd412752214925e0de28887ed54 (patch)
tree3ac83e6200ea1ffb2178e63fe075a543649b3244
parent741e62541882e96e46adeafcda43205e67f81443 (diff)
parent4bc7daf91a0d9102fa477b199964e7db45066da1 (diff)
Merge release-20210208.0-63-g4bc7daf91 (automated)
-rw-r--r--pkg/sentry/fs/file_overlay.go28
-rw-r--r--pkg/sentry/fs/inode_overlay.go13
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 {