Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[linux-2.6-microblaze.git] / fs / dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index c17fd15..7d24ff7 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1043,6 +1043,31 @@ struct dentry *d_find_alias(struct inode *inode)
 }
 EXPORT_SYMBOL(d_find_alias);
 
+/*
+ *  Caller MUST be holding rcu_read_lock() and be guaranteed
+ *  that inode won't get freed until rcu_read_unlock().
+ */
+struct dentry *d_find_alias_rcu(struct inode *inode)
+{
+       struct hlist_head *l = &inode->i_dentry;
+       struct dentry *de = NULL;
+
+       spin_lock(&inode->i_lock);
+       // ->i_dentry and ->i_rcu are colocated, but the latter won't be
+       // used without having I_FREEING set, which means no aliases left
+       if (likely(!(inode->i_state & I_FREEING) && !hlist_empty(l))) {
+               if (S_ISDIR(inode->i_mode)) {
+                       de = hlist_entry(l->first, struct dentry, d_u.d_alias);
+               } else {
+                       hlist_for_each_entry(de, l, d_u.d_alias)
+                               if (!d_unhashed(de))
+                                       break;
+               }
+       }
+       spin_unlock(&inode->i_lock);
+       return de;
+}
+
 /*
  *     Try to kill dentries associated with this inode.
  * WARNING: you must own a reference to inode.
@@ -2151,8 +2176,8 @@ EXPORT_SYMBOL(d_obtain_root);
  * same inode, only the actual correct case is stored in the dcache for
  * case-insensitive filesystems.
  *
- * For a case-insensitive lookup match and if the the case-exact dentry
- * already exists in in the dcache, use it and return it.
+ * For a case-insensitive lookup match and if the case-exact dentry
+ * already exists in the dcache, use it and return it.
  *
  * If no entry exists with the exact case name, allocate new dentry with
  * the exact case, and return the spliced entry.