tools headers UAPI: Sync drm/i915_drm.h with the kernel sources

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

diff --git a/fs/dcache.c b/fs/dcache.c
index 97e81a8..799d9e4 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -456,23 +456,6 @@ static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry,
        list_lru_isolate_move(lru, &dentry->d_lru, list);
 }
 
-/**
- * d_drop - drop a dentry
- * @dentry: dentry to drop
- *
- * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
- * be found through a VFS lookup any more. Note that this is different from
- * deleting the dentry - d_delete will try to mark the dentry negative if
- * possible, giving a successful _negative_ lookup, while d_drop will
- * just make the cache lookup fail.
- *
- * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
- * reason (NFS timeouts or autofs deletes).
- *
- * __d_drop requires dentry->d_lock
- * ___d_drop doesn't mark dentry as "unhashed"
- *   (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
- */
 static void ___d_drop(struct dentry *dentry)
 {
        struct hlist_bl_head *b;
@@ -501,6 +484,24 @@ void __d_drop(struct dentry *dentry)
 }
 EXPORT_SYMBOL(__d_drop);
 
+/**
+ * d_drop - drop a dentry
+ * @dentry: dentry to drop
+ *
+ * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
+ * be found through a VFS lookup any more. Note that this is different from
+ * deleting the dentry - d_delete will try to mark the dentry negative if
+ * possible, giving a successful _negative_ lookup, while d_drop will
+ * just make the cache lookup fail.
+ *
+ * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
+ * reason (NFS timeouts or autofs deletes).
+ *
+ * __d_drop requires dentry->d_lock
+ *
+ * ___d_drop doesn't mark dentry as "unhashed"
+ * (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
+ */
 void d_drop(struct dentry *dentry)
 {
        spin_lock(&dentry->d_lock);
@@ -996,20 +997,6 @@ struct dentry *d_find_any_alias(struct inode *inode)
 }
 EXPORT_SYMBOL(d_find_any_alias);
 
-/**
- * d_find_alias - grab a hashed alias of inode
- * @inode: inode in question
- *
- * If inode has a hashed alias, or is a directory and has any alias,
- * acquire the reference to alias and return it. Otherwise return NULL.
- * Notice that if inode is a directory there can be only one alias and
- * it can be unhashed only if it has no children, or if it is the root
- * of a filesystem, or if the directory was renamed and d_revalidate
- * was the first vfs operation to notice.
- *
- * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
- * any other hashed alias over that one.
- */
 static struct dentry *__d_find_alias(struct inode *inode)
 {
        struct dentry *alias;
@@ -1029,6 +1016,20 @@ static struct dentry *__d_find_alias(struct inode *inode)
        return NULL;
 }
 
+/**
+ * d_find_alias - grab a hashed alias of inode
+ * @inode: inode in question
+ *
+ * If inode has a hashed alias, or is a directory and has any alias,
+ * acquire the reference to alias and return it. Otherwise return NULL.
+ * Notice that if inode is a directory there can be only one alias and
+ * it can be unhashed only if it has no children, or if it is the root
+ * of a filesystem, or if the directory was renamed and d_revalidate
+ * was the first vfs operation to notice.
+ *
+ * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
+ * any other hashed alias over that one.
+ */
 struct dentry *d_find_alias(struct inode *inode)
 {
        struct dentry *de = NULL;
@@ -1042,6 +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.