[PATCH RFC 5/8] dcache: add action D_WALK_SKIP_SIBLINGS to d_walk()

[Konstantin Khlebnikov <khlebnikov@yandex-team.ru>]

This lets skip remaining siblings at seeing d_is_tail_negative().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 fs/dcache.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/dcache.c b/fs/dcache.c
index 743255773cc7..44c6832d21d6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1303,12 +1303,14 @@ EXPORT_SYMBOL(shrink_dcache_sb);
  * @D_WALK_QUIT:	quit walk
  * @D_WALK_NORETRY:	quit when retry is needed
  * @D_WALK_SKIP:	skip this dentry and its children
+ * @D_WALK_SKIP_SIBLINGS: skip siblings and their children
  */
 enum d_walk_ret {
 	D_WALK_CONTINUE,
 	D_WALK_QUIT,
 	D_WALK_NORETRY,
 	D_WALK_SKIP,
+	D_WALK_SKIP_SIBLINGS,
 };
 
 /**
@@ -1339,6 +1341,7 @@ static void d_walk(struct dentry *parent, void *data,
 		break;
 	case D_WALK_QUIT:
 	case D_WALK_SKIP:
+	case D_WALK_SKIP_SIBLINGS:
 		goto out_unlock;
 	case D_WALK_NORETRY:
 		retry = false;
@@ -1370,6 +1373,9 @@ static void d_walk(struct dentry *parent, void *data,
 		case D_WALK_SKIP:
 			spin_unlock(&dentry->d_lock);
 			continue;
+		case D_WALK_SKIP_SIBLINGS:
+			spin_unlock(&dentry->d_lock);
+			goto skip_siblings;
 		}
 
 		if (!list_empty(&dentry->d_subdirs)) {
@@ -1381,6 +1387,7 @@ static void d_walk(struct dentry *parent, void *data,
 		}
 		spin_unlock(&dentry->d_lock);
 	}
+skip_siblings:
 	/*
 	 * All done at this level ... ascend and resume the search.
 	 */