vfs: use ancestryMu in implementations of DentryImpl.InotifyWithParent

This lock was introduced in cl/696713993 and only protects parent/name for all
dentries, which is all that's required by InotifyWithParent().

PiperOrigin-RevId: 697016824

pkg/sentry/fsimpl/gofer/gofer.go

@@ -1544,13 +1544,13 @@ func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, e
 		events |= linux.IN_ISDIR
 	}
 
-	d.fs.renameMu.RLock()
+	d.fs.ancestryMu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	if parent := d.parent.Load(); parent != nil {
 		parent.watches.Notify(ctx, d.name, events, cookie, et, d.isDeleted())
 	}
 	d.watches.Notify(ctx, "", events, cookie, et, d.isDeleted())
-	d.fs.renameMu.RUnlock()
+	d.fs.ancestryMu.RUnlock()
 }
 
 // Watches implements vfs.DentryImpl.Watches.

pkg/sentry/fsimpl/kernfs/kernfs.go

@@ -541,11 +541,11 @@ func (d *Dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, e
 	// Don't bother looking for a parent if the inode is anonymous. It
 	// won't have one.
 	if !d.inode.Anonymous() {
-		d.fs.mu.RLock()
+		d.fs.ancestryMu.RLock()
 		if parent := d.parent.Load(); parent != nil {
 			parent.inode.Watches().Notify(ctx, d.name, events, cookie, et, d.isDeleted())
 		}
-		d.fs.mu.RUnlock()
+		d.fs.ancestryMu.RUnlock()
 	}
 
 	d.inode.Watches().Notify(ctx, "", events, cookie, et, d.isDeleted())

pkg/sentry/fsimpl/overlay/overlay.go

@@ -748,13 +748,13 @@ func (d *dentry) InotifyWithParent(ctx context.Context, events uint32, cookie ui
 	// that d was deleted.
 	deleted := d.vfsd.IsDead()
 
-	d.fs.renameMu.RLock()
+	d.fs.ancestryMu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	if parent := d.parent.Load(); parent != nil {
 		parent.watches.Notify(ctx, d.name, events, cookie, et, deleted)
 	}
 	d.watches.Notify(ctx, "", events, cookie, et, deleted)
-	d.fs.renameMu.RUnlock()
+	d.fs.ancestryMu.RUnlock()
 }
 
 // Watches implements vfs.DentryImpl.Watches.

pkg/sentry/fsimpl/tmpfs/tmpfs.go

@@ -442,14 +442,14 @@ func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, e
 	// that d was deleted.
 	deleted := d.vfsd.IsDead()
 
-	d.inode.fs.mu.RLock()
+	d.inode.fs.ancestryMu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	parent := d.parent.Load()
 	if parent != nil {
 		parent.inode.watches.Notify(ctx, d.name, events, cookie, et, deleted)
 	}
 	d.inode.watches.Notify(ctx, "", events, cookie, et, deleted)
-	d.inode.fs.mu.RUnlock()
+	d.inode.fs.ancestryMu.RUnlock()
 }
 
 // Watches implements vfs.DentryImpl.Watches.

pkg/sentry/vfs/vfs.go

@@ -18,11 +18,11 @@
 //
 //	EpollInstance.interestMu
 //		FileDescription.epollMu
-//		  Locks acquired by FilesystemImpl/FileDescriptionImpl methods (except FilesystemImpl.PrependPath and IsDescendant)
+//		  Locks acquired by FilesystemImpl/DentryImpl/FileDescriptionImpl methods (except FilesystemImpl.PrependPath, FilesystemImpl.IsDescendant, DentryImpl.InotifyWithParent)
 //		    VirtualFilesystem.mountMu
 //		      Dentry.mu
 //		        Locks acquired by FilesystemImpls between Prepare{Delete,Rename}Dentry and Commit{Delete,Rename*}Dentry
-//		          Locks acquired by FilesystemImpl.PrependPath and IsDescendant (typically genericfstree.Filesystem.ancestryMu)
+//		          Locks acquired by FilesystemImpl.PrependPath, FilesystemImpl.IsDescendant, DentryImpl.InotifyWithParent (typically genericfstree.Filesystem.ancestryMu)
 //		      VirtualFilesystem.filesystemsMu
 //		    fdnotifier.notifier.mu
 //		      EpollInstance.readyMu