fold dentry_lock_for_move() into its sole caller and clean it up

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

diff --git a/fs/dcache.c b/fs/dcache.c
index 0a58038091f296f57ca70c7e10ae96761a8e1acf..c159a4b304cfb395c6fab62c76351b5a06405c5e 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2773,25 +2773,6 @@ static void copy_name(struct dentry *dentry, struct dentry *target)
                kfree_rcu(old_name, u.head);
 }
 
-static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
-{
-       if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent)
-               spin_lock(&target->d_parent->d_lock);
-       else {
-               if (d_ancestor(dentry->d_parent, target->d_parent)) {
-                       spin_lock(&dentry->d_parent->d_lock);
-                       spin_lock_nested(&target->d_parent->d_lock,
-                                               DENTRY_D_LOCK_NESTED);
-               } else {
-                       spin_lock(&target->d_parent->d_lock);
-                       spin_lock_nested(&dentry->d_parent->d_lock,
-                                               DENTRY_D_LOCK_NESTED);
-               }
-       }
-       spin_lock_nested(&dentry->d_lock, 2);
-       spin_lock_nested(&target->d_lock, 3);
-}
-
 /*
  * __d_move - move a dentry
  * @dentry: entry to move
@@ -2806,16 +2787,34 @@ static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
 static void __d_move(struct dentry *dentry, struct dentry *target,
                     bool exchange)
 {
-       struct dentry *old_parent;
+       struct dentry *old_parent, *p;
        struct inode *dir = NULL;
        unsigned n;
-       if (!dentry->d_inode)
-               printk(KERN_WARNING "VFS: moving negative dcache entry\n");
 
-       BUG_ON(d_ancestor(dentry, target));
+       WARN_ON(!dentry->d_inode);
+       if (WARN_ON(dentry == target))
+               return;
+
        BUG_ON(d_ancestor(target, dentry));
+       old_parent = dentry->d_parent;
+       p = d_ancestor(old_parent, target);
+       if (IS_ROOT(dentry)) {
+               BUG_ON(p);
+               spin_lock(&target->d_parent->d_lock);
+       } else if (!p) {
+               /* target is not a descendent of dentry->d_parent */
+               spin_lock(&target->d_parent->d_lock);
+               spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED);
+       } else {
+               BUG_ON(p == dentry);
+               spin_lock(&old_parent->d_lock);
+               if (p != target)
+                       spin_lock_nested(&target->d_parent->d_lock,
+                                       DENTRY_D_LOCK_NESTED);
+       }
+       spin_lock_nested(&dentry->d_lock, 2);
+       spin_lock_nested(&target->d_lock, 3);
 
-       dentry_lock_for_move(dentry, target);
        if (unlikely(d_in_lookup(target))) {
                dir = target->d_parent->d_inode;
                n = start_dir_add(dir);
@@ -2825,8 +2824,6 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
        write_seqcount_begin(&dentry->d_seq);
        write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
 
-       old_parent = dentry->d_parent;
-
        /* unhash both */
        if (!d_unhashed(dentry))
                ___d_drop(dentry);