Merge release-20200608.0-112-g0c628c315 (automated)

3 files changed, 20 insertions, 15 deletions

diff --git a/pkg/sentry/fsimpl/tmpfs/directory.go b/pkg/sentry/fsimpl/tmpfs/directory.go
index 913b8a6c5..b172abc15 100644
--- a/pkg/sentry/fsimpl/tmpfs/directory.go
+++ b/pkg/sentry/fsimpl/tmpfs/directory.go
@@ -79,7 +79,6 @@ func (dir *directory) removeChildLocked(child *dentry) {
 	dir.iterMu.Lock()
 	dir.childList.Remove(child)
 	dir.iterMu.Unlock()
-	child.unlinked = true
 }
 
 type directoryFD struct {
@@ -107,13 +106,14 @@ func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallba
 	fs := fd.filesystem()
 	dir := fd.inode().impl.(*directory)
 
+	defer fd.dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
+
 	// fs.mu is required to read d.parent and dentry.name.
 	fs.mu.RLock()
 	defer fs.mu.RUnlock()
 	dir.iterMu.Lock()
 	defer dir.iterMu.Unlock()
 
-	fd.dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
 	fd.inode().touchAtime(fd.vfsfd.Mount())
 
 	if fd.off == 0 {
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 637d84e04..85d8e37b2 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -638,14 +638,16 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
 // SetStatAt implements vfs.FilesystemImpl.SetStatAt.
 func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error {
 	fs.mu.RLock()
-	defer fs.mu.RUnlock()
 	d, err := resolveLocked(rp)
 	if err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
 	if err := d.inode.setStat(ctx, rp.Credentials(), &opts.Stat); err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
+	fs.mu.RUnlock()
 
 	if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 {
 		d.InotifyWithParent(ev, 0, vfs.InodeEvent)
@@ -788,14 +790,16 @@ func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt
 // SetxattrAt implements vfs.FilesystemImpl.SetxattrAt.
 func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error {
 	fs.mu.RLock()
-	defer fs.mu.RUnlock()
 	d, err := resolveLocked(rp)
 	if err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
 	if err := d.inode.setxattr(rp.Credentials(), &opts); err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
+	fs.mu.RUnlock()
 
 	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
 	return nil
@@ -804,14 +808,16 @@ func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt
 // RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt.
 func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error {
 	fs.mu.RLock()
-	defer fs.mu.RUnlock()
 	d, err := resolveLocked(rp)
 	if err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
 	if err := d.inode.removexattr(rp.Credentials(), name); err != nil {
+		fs.mu.RUnlock()
 		return err
 	}
+	fs.mu.RUnlock()
 
 	d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
 	return nil
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index a94333ee0..a85bfc968 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -215,11 +215,6 @@ type dentry struct {
 	// filesystem.mu.
 	name string
 
-	// unlinked indicates whether this dentry has been unlinked from its parent.
-	// It is only set to true on an unlink operation, and never set from true to
-	// false. unlinked is protected by filesystem.mu.
-	unlinked bool
-
 	// dentryEntry (ugh) links dentries into their parent directory.childList.
 	dentryEntry
 
@@ -259,18 +254,20 @@ func (d *dentry) DecRef() {
 }
 
 // InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
-func (d *dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {
+func (d *dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {
 	if d.inode.isDir() {
 		events |= linux.IN_ISDIR
 	}
 
+	d.inode.fs.mu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	if d.parent != nil {
-		// Note that d.parent or d.name may be stale if there is a concurrent
-		// rename operation. Inotify does not provide consistency guarantees.
-		d.parent.inode.watches.NotifyWithExclusions(d.name, events, cookie, et, d.unlinked)
+		// tmpfs never calls VFS.InvalidateDentry(), so d.vfsd.IsDead() indicates
+		// that d was deleted.
+		d.parent.inode.watches.NotifyWithExclusions(d.name, events, cookie, et, d.vfsd.IsDead())
 	}
 	d.inode.watches.Notify("", events, cookie, et)
+	d.inode.fs.mu.RUnlock()
 }
 
 // Watches implements vfs.DentryImpl.Watches.
@@ -278,6 +275,9 @@ func (d *dentry) Watches() *vfs.Watches {
 	return &d.inode.watches
 }
 
+// OnZeroWatches implements vfs.Dentry.OnZeroWatches.
+func (d *dentry) OnZeroWatches() {}
+
 // inode represents a filesystem object.
 type inode struct {
 	// fs is the owning filesystem. fs is immutable.
@@ -336,7 +336,6 @@ func (i *inode) init(impl interface{}, fs *filesystem, kuid auth.KUID, kgid auth
 	i.ctime = now
 	i.mtime = now
 	// i.nlink initialized by caller
-	i.watches = vfs.Watches{}
 	i.impl = impl
 }