Merge tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull dcache updates from Al Viro:
 "Change of locking rules for __dentry_kill(), regularized refcounting
  rules in that area, assorted cleanups and removal of weird corner
  cases (e.g. now ->d_iput() on child is always called before the parent
  might hit __dentry_kill(), etc)"

* tag 'pull-dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
  dcache: remove unnecessary NULL check in dget_dlock()
  kill DCACHE_MAY_FREE
  __d_unalias() doesn't use inode argument
  d_alloc_parallel(): in-lookup hash insertion doesn't need an RCU variant
  get rid of DCACHE_GENOCIDE
  d_genocide(): move the extern into fs/internal.h
  simple_fill_super(): don't bother with d_genocide() on failure
  nsfs: use d_make_root()
  d_alloc_pseudo(): move setting ->d_op there from the (sole) caller
  kill d_instantate_anon(), fold __d_instantiate_anon() into remaining caller
  retain_dentry(): introduce a trimmed-down lockless variant
  __dentry_kill(): new locking scheme
  d_prune_aliases(): use a shrink list
  switch select_collect{,2}() to use of to_shrink_list()
  to_shrink_list(): call only if refcount is 0
  fold dentry_kill() into dput()
  don't try to cut corners in shrink_lock_dentry()
  fold the call of retain_dentry() into fast_dput()
  Call retain_dentry() with refcount 0
  dentry_kill(): don't bother with retain_dentry() on slow path
  ...

1 files changed, 14 insertions, 19 deletions

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index bc86ffdb103b..ad20e6af938d 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -199,21 +199,17 @@ static void change_gid(struct dentry *dentry, kgid_t gid)
  */
 static void set_gid(struct dentry *parent, kgid_t gid)
 {
-	struct dentry *this_parent;
-	struct list_head *next;
+	struct dentry *this_parent, *dentry;
 
 	this_parent = parent;
 	spin_lock(&this_parent->d_lock);
 
 	change_gid(this_parent, gid);
 repeat:
-	next = this_parent->d_subdirs.next;
+	dentry = d_first_child(this_parent);
 resume:
-	while (next != &this_parent->d_subdirs) {
+	hlist_for_each_entry_from(dentry, d_sib) {
 		struct tracefs_inode *ti;
-		struct list_head *tmp = next;
-		struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
-		next = tmp->next;
 
 		/* Note, getdents() can add a cursor dentry with no inode */
 		if (!dentry->d_inode)
@@ -228,7 +224,7 @@ resume:
 		if (ti && (ti->flags & TRACEFS_EVENT_INODE))
 			eventfs_update_gid(dentry, gid);
 
-		if (!list_empty(&dentry->d_subdirs)) {
+		if (!hlist_empty(&dentry->d_children)) {
 			spin_unlock(&this_parent->d_lock);
 			spin_release(&dentry->d_lock.dep_map, _RET_IP_);
 			this_parent = dentry;
@@ -243,21 +239,20 @@ resume:
 	rcu_read_lock();
 ascend:
 	if (this_parent != parent) {
-		struct dentry *child = this_parent;
-		this_parent = child->d_parent;
+		dentry = this_parent;
+		this_parent = dentry->d_parent;
 
-		spin_unlock(&child->d_lock);
+		spin_unlock(&dentry->d_lock);
 		spin_lock(&this_parent->d_lock);
 
 		/* go into the first sibling still alive */
-		do {
-			next = child->d_child.next;
-			if (next == &this_parent->d_subdirs)
-				goto ascend;
-			child = list_entry(next, struct dentry, d_child);
-		} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
-		rcu_read_unlock();
-		goto resume;
+		hlist_for_each_entry_continue(dentry, d_sib) {
+			if (likely(!(dentry->d_flags & DCACHE_DENTRY_KILLED))) {
+				rcu_read_unlock();
+				goto resume;
+			}
+		}
+		goto ascend;
 	}
 	rcu_read_unlock();
 	spin_unlock(&this_parent->d_lock);