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

Pull vfs dcache updates from Al Viro:
 "The main part here is making parallel lookups safe for RT - making
  sure preemption is disabled in start_dir_add()/ end_dir_add() sections
  (on non-RT it's automatic, on RT it needs to to be done explicitly)
  and moving wakeups from __d_lookup_done() inside of such to the end of
  those sections.

  Wakeups can be safely delayed for as long as ->d_lock on in-lookup
  dentry is held; proving that has caught a bug in d_add_ci() that
  allows memory corruption when sufficiently bogus ntfs (or
  case-insensitive xfs) image is mounted. Easily fixed, fortunately"

* tag 'pull-work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs/dcache: Move wakeup out of i_seq_dir write held region.
  fs/dcache: Move the wakeup from __d_lookup_done() to the caller.
  fs/dcache: Disable preemption on i_dir_seq write side on PREEMPT_RT
  d_add_ci(): make sure we don't miss d_lookup_done()

1 files changed, 3 insertions, 6 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index f5bba51480b2..c73e5e327e76 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -349,7 +349,7 @@ static inline void dont_mount(struct dentry *dentry)
 	spin_unlock(&dentry->d_lock);
 }
 
-extern void __d_lookup_done(struct dentry *);
+extern void __d_lookup_unhash_wake(struct dentry *dentry);
 
 static inline int d_in_lookup(const struct dentry *dentry)
 {
@@ -358,11 +358,8 @@ static inline int d_in_lookup(const struct dentry *dentry)
 
 static inline void d_lookup_done(struct dentry *dentry)
 {
-	if (unlikely(d_in_lookup(dentry))) {
-		spin_lock(&dentry->d_lock);
-		__d_lookup_done(dentry);
-		spin_unlock(&dentry->d_lock);
-	}
+	if (unlikely(d_in_lookup(dentry)))
+		__d_lookup_unhash_wake(dentry);
 }
 
 extern void dput(struct dentry *);