split dentry_kill()

... into trylocks and everything else.  The latter (actual killing)
is __dentry_kill().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 36 insertions, 26 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 6888dde4d568..1577c14dfb4e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -441,36 +441,12 @@ void d_drop(struct dentry *dentry)
 }
 EXPORT_SYMBOL(d_drop);
 
-/*
- * Finish off a dentry we've decided to kill.
- * dentry->d_lock must be held, returns with it unlocked.
- * If ref is non-zero, then decrement the refcount too.
- * Returns dentry requiring refcount drop, or NULL if we're done.
- */
-static struct dentry *
-dentry_kill(struct dentry *dentry, int unlock_on_failure)
-        __releases(dentry->d_lock)
+static void __dentry_kill(struct dentry *dentry)
 {
-        struct inode *inode;
         struct dentry *parent = NULL;
         bool can_free = true;
-
-        inode = dentry->d_inode;
-        if (inode && !spin_trylock(&inode->i_lock)) {
-relock:
-                if (unlock_on_failure) {
-                        spin_unlock(&dentry->d_lock);
-                        cpu_relax();
-                }
-                return dentry; /* try again with same dentry */
-        }
         if (!IS_ROOT(dentry))
                 parent = dentry->d_parent;
-        if (parent && !spin_trylock(&parent->d_lock)) {
-                if (inode)
-                        spin_unlock(&inode->i_lock);
-                goto relock;
-        }
 
         /*
          * The dentry is now unrecoverably dead to the world.
@@ -514,10 +490,44 @@ relock:
                 can_free = false;
         }
         spin_unlock(&dentry->d_lock);
-out:
         if (likely(can_free))
                 dentry_free(dentry);
+}
+
+/*
+ * Finish off a dentry we've decided to kill.
+ * dentry->d_lock must be held, returns with it unlocked.
+ * If ref is non-zero, then decrement the refcount too.
+ * Returns dentry requiring refcount drop, or NULL if we're done.
+ */
+static struct dentry *
+dentry_kill(struct dentry *dentry, int unlock_on_failure)
+        __releases(dentry->d_lock)
+{
+        struct inode *inode = dentry->d_inode;
+        struct dentry *parent = NULL;
+
+        if (inode && unlikely(!spin_trylock(&inode->i_lock)))
+                goto failed;
+
+        if (!IS_ROOT(dentry)) {
+                parent = dentry->d_parent;
+                if (unlikely(!spin_trylock(&parent->d_lock))) {
+                        if (inode)
+                                spin_unlock(&inode->i_lock);
+                        goto failed;
+                }
+        }
+
+        __dentry_kill(dentry);
         return parent;
+
+failed:
+        if (unlock_on_failure) {
+                spin_unlock(&dentry->d_lock);
+                cpu_relax();
+        }
+        return dentry; /* try again with same dentry */
 }
 
 /*